FileDocCategorySizeDatePackage
String.javaAPI DocJava SE 5 API108600Fri Aug 26 14:57:04 BST 2005java.lang

String

public final class String extends Object implements CharSequence, Serializable, Comparable
The String class represents character strings. All string literals in Java programs, such as "abc", are implemented as instances of this class.

Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings. Because String objects are immutable they can be shared. For example:

String str = "abc";

is equivalent to:

char data[] = {'a', 'b', 'c'};
String str = new String(data);

Here are some more examples of how strings can be used:

System.out.println("abc");
String cde = "cde";
System.out.println("abc" + cde);
String c = "abc".substring(2,3);
String d = cde.substring(1, 2);

The class String includes methods for examining individual characters of the sequence, for comparing strings, for searching strings, for extracting substrings, and for creating a copy of a string with all characters translated to uppercase or to lowercase. Case mapping is based on the Unicode Standard version specified by the {@link java.lang.Character Character} class.

The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings. String concatenation is implemented through the StringBuilder(or StringBuffer) class and its append method. String conversions are implemented through the method toString, defined by Object and inherited by all classes in Java. For additional information on string concatenation and conversion, see Gosling, Joy, and Steele, The Java Language Specification.

Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a {@link NullPointerException} to be thrown.

A String represents a string in the UTF-16 format in which supplementary characters are represented by surrogate pairs (see the section Unicode Character Representations in the Character class for more information). Index values refer to char code units, so a supplementary character uses two positions in a String.

The String class provides methods for dealing with Unicode code points (i.e., characters), in addition to those for dealing with Unicode code units (i.e., char values).

author
Lee Boynton
author
Arthur van Hoff
version
1.188, 09/14/04
see
java.lang.Object#toString()
see
java.lang.StringBuffer
see
java.lang.StringBuilder
see
java.nio.charset.Charset
since
JDK1.0

Fields Summary
private final char[]
value
The value is used for character storage.
private final int
offset
The offset is the first index of the storage that is used.
private final int
count
The count is the number of characters in the String.
private int
hash
Cache the hash code for the string
private static final long
serialVersionUID
use serialVersionUID from JDK 1.0.2 for interoperability
private static final ObjectStreamField[]
serialPersistentFields
Class String is special cased within the Serialization Stream Protocol. A String instance is written initially into an ObjectOutputStream in the following format:
TC_STRING (utf String)
The String is written by method DataOutput.writeUTF. A new handle is generated to refer to all future references to the string instance within the stream.
public static final Comparator
CASE_INSENSITIVE_ORDER
A Comparator that orders String objects as by compareToIgnoreCase. This comparator is serializable.

Note that this Comparator does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides Collators to allow locale-sensitive ordering.

Constructors Summary
public String()
Initializes a newly created String object so that it represents an empty character sequence. Note that use of this constructor is unnecessary since Strings are immutable.


                                      
      
	this.offset = 0;
	this.count = 0;
	this.value = new char[0];
    
public String(byte[] bytes, String charsetName)
Constructs a new String by decoding the specified array of bytes using the specified charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the byte array.

The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The {@link java.nio.charset.CharsetDecoder} class should be used when more control over the decoding process is required.

param
bytes the bytes to be decoded into characters
param
charsetName the name of a supported {@link java.nio.charset.Charset charset}
exception
UnsupportedEncodingException If the named charset is not supported
since
JDK1.1

	this(bytes, 0, bytes.length, charsetName);
    
public String(byte[] bytes, int offset, int length)
Constructs a new String by decoding the specified subarray of bytes using the platform's default charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the subarray.

The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The {@link java.nio.charset.CharsetDecoder} class should be used when more control over the decoding process is required.

param
bytes the bytes to be decoded into characters
param
offset the index of the first byte to decode
param
length the number of bytes to decode
throws
IndexOutOfBoundsException if the offset and the length arguments index characters outside the bounds of the bytes array
since
JDK1.1

	checkBounds(bytes, offset, length);
	char[] v  = StringCoding.decode(bytes, offset, length);
	this.offset = 0;
	this.count = v.length;
	this.value = v;
    
public String(byte[] bytes)
Constructs a new String by decoding the specified array of bytes using the platform's default charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the byte array.

The behavior of this constructor when the given bytes are not valid in the default charset is unspecified. The {@link java.nio.charset.CharsetDecoder} class should be used when more control over the decoding process is required.

param
bytes the bytes to be decoded into characters
since
JDK1.1

	this(bytes, 0, bytes.length);
    
public String(StringBuffer buffer)
Allocates a new string that contains the sequence of characters currently contained in the string buffer argument. The contents of the string buffer are copied; subsequent modification of the string buffer does not affect the newly created string.

param
buffer a StringBuffer.

        String result = buffer.toString();
        this.value = result.value;
        this.count = result.count;
        this.offset = result.offset;
    
public String(StringBuilder builder)
Allocates a new string that contains the sequence of characters currently contained in the string builder argument. The contents of the string builder are copied; subsequent modification of the string builder does not affect the newly created string.

This constructor is provided to ease migration to StringBuilder. Obtaining a string from a string builder via the toString method is likely to run faster and is generally preferred.

param
builder a StringBuilder
since
1.5

        String result = builder.toString();
        this.value = result.value;
        this.count = result.count;
        this.offset = result.offset;
    
String(int offset, int count, char[] value)

	this.value = value;
	this.offset = offset;
	this.count = count;
    
public String(String original)
Initializes a newly created String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of original is needed, use of this constructor is unnecessary since Strings are immutable.

param
original a String.

	int size = original.count;
	char[] originalValue = original.value;
	char[] v;
  	if (originalValue.length > size) {
 	    // The array representing the String is bigger than the new
 	    // String itself.  Perhaps this constructor is being called
 	    // in order to trim the baggage, so make a copy of the array.
	    v = new char[size];
 	    System.arraycopy(originalValue, original.offset, v, 0, size);
 	} else {
 	    // The array representing the String is the same
 	    // size as the String, so no point in making a copy.
	    v = originalValue;
 	}
	this.offset = 0;
	this.count = size;
	this.value = v;
    
public String(char[] value)
Allocates a new String so that it represents the sequence of characters currently contained in the character array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.

param
value the initial value of the string.

	int size = value.length;
	char[] v = new char[size];
	System.arraycopy(value, 0, v, 0, size);
	this.offset = 0;
	this.count = size;
	this.value = v;
    
public String(char[] value, int offset, int count)
Allocates a new String that contains characters from a subarray of the character array argument. The offset argument is the index of the first character of the subarray and the count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.

param
value array that is the source of characters.
param
offset the initial offset.
param
count the length.
exception
IndexOutOfBoundsException if the offset and count arguments index characters outside the bounds of the value array.

        if (offset < 0) {
            throw new StringIndexOutOfBoundsException(offset);
        }
        if (count < 0) {
            throw new StringIndexOutOfBoundsException(count);
        }
        // Note: offset or count might be near -1>>>1.
        if (offset > value.length - count) {
            throw new StringIndexOutOfBoundsException(offset + count);
        }
        char[] v = new char[count];
        System.arraycopy(value, offset, v, 0, count);
        this.offset = 0;
        this.count = count;
        this.value = v;
    
public String(int[] codePoints, int offset, int count)
Allocates a new String that contains characters from a subarray of the Unicode code point array argument. The offset argument is the index of the first code point of the subarray and the count argument specifies the length of the subarray. The contents of the subarray are converted to chars; subsequent modification of the int array does not affect the newly created string.

param
codePoints array that is the source of Unicode code points.
param
offset the initial offset.
param
count the length.
exception
IllegalArgumentException if any invalid Unicode code point is found in codePoints
exception
IndexOutOfBoundsException if the offset and count arguments index characters outside the bounds of the codePoints array.
since
1.5

        if (offset < 0) {
            throw new StringIndexOutOfBoundsException(offset);
        }
        if (count < 0) {
            throw new StringIndexOutOfBoundsException(count);
        }
        // Note: offset or count might be near -1>>>1.
        if (offset > codePoints.length - count) {
            throw new StringIndexOutOfBoundsException(offset + count);
        }

	int expansion = 0;
	int margin = 1;
	char[] v = new char[count + margin];
	int x = offset;
	int j = 0;
	for (int i = 0; i < count; i++) {
	    int c = codePoints[x++];
	    if (c < 0) {
		throw new IllegalArgumentException();
	    }
	    if (margin <= 0 && (j+1) >= v.length) {
		if (expansion == 0) {
		    expansion = (((-margin + 1) * count) << 10) / i;
		    expansion >>= 10;
		    if (expansion <= 0) {
			expansion = 1;
		    }
		} else {
		    expansion *= 2;
		}
		char[] tmp = new char[Math.min(v.length+expansion, count*2)];
		margin = (tmp.length - v.length) - (count - i);
		System.arraycopy(v, 0, tmp, 0, j);
		v = tmp;
	    }
	    if (c < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
		v[j++] = (char) c;
	    } else if (c <= Character.MAX_CODE_POINT) {
		Character.toSurrogates(c, v, j);
		j += 2;
		margin--;
	    } else {
		throw new IllegalArgumentException();
	    }
	}
	this.offset = 0;
	this.value = v;
	this.count = j;
    
public String(byte[] ascii, int hibyte, int offset, int count)
Allocates a new String constructed from a subarray of an array of 8-bit integer values.

The offset argument is the index of the first byte of the subarray, and the count argument specifies the length of the subarray.

Each byte in the subarray is converted to a char as specified in the method above.

deprecated
This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a charset name or that use the platform's default charset.
param
ascii the bytes to be converted to characters.
param
hibyte the top 8 bits of each 16-bit Unicode character.
param
offset the initial offset.
param
count the length.
exception
IndexOutOfBoundsException if the offset or count argument is invalid.
see
java.lang.String#String(byte[], int)
see
java.lang.String#String(byte[], int, int, java.lang.String)
see
java.lang.String#String(byte[], int, int)
see
java.lang.String#String(byte[], java.lang.String)
see
java.lang.String#String(byte[])

	checkBounds(ascii, offset, count);
        char value[] = new char[count];

        if (hibyte == 0) {
            for (int i = count ; i-- > 0 ;) {
                value[i] = (char) (ascii[i + offset] & 0xff);
            }
        } else {
            hibyte <<= 8;
            for (int i = count ; i-- > 0 ;) {
                value[i] = (char) (hibyte | (ascii[i + offset] & 0xff));
            }
        }
	this.offset = 0;
	this.count = count;
	this.value = value;
    
public String(byte[] ascii, int hibyte)
Allocates a new String containing characters constructed from an array of 8-bit integer values. Each character cin the resulting string is constructed from the corresponding component b in the byte array such that:

c == (char)(((hibyte & 0xff) << 8)
| (b & 0xff))

deprecated
This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the String constructors that take a charset name or that use the platform's default charset.
param
ascii the bytes to be converted to characters.
param
hibyte the top 8 bits of each 16-bit Unicode character.
see
java.lang.String#String(byte[], int, int, java.lang.String)
see
java.lang.String#String(byte[], int, int)
see
java.lang.String#String(byte[], java.lang.String)
see
java.lang.String#String(byte[])

        this(ascii, hibyte, 0, ascii.length);
    
public String(byte[] bytes, int offset, int length, String charsetName)
Constructs a new String by decoding the specified subarray of bytes using the specified charset. The length of the new String is a function of the charset, and hence may not be equal to the length of the subarray.

The behavior of this constructor when the given bytes are not valid in the given charset is unspecified. The {@link java.nio.charset.CharsetDecoder} class should be used when more control over the decoding process is required.

param
bytes the bytes to be decoded into characters
param
offset the index of the first byte to decode
param
length the number of bytes to decode
param
charsetName the name of a supported {@link java.nio.charset.Charset charset}
throws
UnsupportedEncodingException if the named charset is not supported
throws
IndexOutOfBoundsException if the offset and length arguments index characters outside the bounds of the bytes array
since
JDK1.1

	if (charsetName == null)
	    throw new NullPointerException("charsetName");
	checkBounds(bytes, offset, length);
	char[] v = StringCoding.decode(charsetName, bytes, offset, length);
	this.offset = 0;
	this.count = v.length;
	this.value = v;
    
Methods Summary
public charcharAt(int index)
Returns the char value at the specified index. An index ranges from 0 to length() - 1. The first char value of the sequence is at index 0, the next at index 1, and so on, as for array indexing.

If the char value specified by the index is a surrogate, the surrogate value is returned.

param
index the index of the char value.
return
the char value at the specified index of this string. The first char value is at index 0.
exception
IndexOutOfBoundsException if the index argument is negative or not less than the length of this string.

        if ((index < 0) || (index >= count)) {
            throw new StringIndexOutOfBoundsException(index);
        }
        return value[index + offset];
    
private static voidcheckBounds(byte[] bytes, int offset, int length)

	if (length < 0)
	    throw new StringIndexOutOfBoundsException(length);
	if (offset < 0)
	    throw new StringIndexOutOfBoundsException(offset);
	if (offset > bytes.length - length)
	    throw new StringIndexOutOfBoundsException(offset + length);
    
public intcodePointAt(int index)
Returns the character (Unicode code point) at the specified index. The index refers to char values (Unicode code units) and ranges from 0 to {@link #length()} - 1.

If the char value specified at the given index is in the high-surrogate range, the following index is less than the length of this String, and the char value at the following index is in the low-surrogate range, then the supplementary code point corresponding to this surrogate pair is returned. Otherwise, the char value at the given index is returned.

param
index the index to the char values
return
the code point value of the character at the index
exception
IndexOutOfBoundsException if the index argument is negative or not less than the length of this string.
since
1.5

        if ((index < 0) || (index >= count)) {
            throw new StringIndexOutOfBoundsException(index);
        }
        return Character.codePointAtImpl(value, offset + index, offset + count);
    
public intcodePointBefore(int index)
Returns the character (Unicode code point) before the specified index. The index refers to char values (Unicode code units) and ranges from 1 to {@link CharSequence#length() length}.

If the char value at (index - 1) is in the low-surrogate range, (index - 2) is not negative, and the char value at (index - 2) is in the high-surrogate range, then the supplementary code point value of the surrogate pair is returned. If the char value at index - 1 is an unpaired low-surrogate or a high-surrogate, the surrogate value is returned.

param
index the index following the code point that should be returned
return
the Unicode code point value before the given index.
exception
IndexOutOfBoundsException if the index argument is less than 1 or greater than the length of this string.
since
1.5

	int i = index - 1;
        if ((i < 0) || (i >= count)) {
            throw new StringIndexOutOfBoundsException(index);
        }
        return Character.codePointBeforeImpl(value, offset + index, offset); 
    
public intcodePointCount(int beginIndex, int endIndex)
Returns the number of Unicode code points in the specified text range of this String. The text range begins at the specified beginIndex and extends to the char at index endIndex - 1. Thus the length (in chars) of the text range is endIndex-beginIndex. Unpaired surrogates within the text range count as one code point each.

param
beginIndex the index to the first char of the text range.
param
endIndex the index after the last char of the text range.
return
the number of Unicode code points in the specified text range
exception
IndexOutOfBoundsException if the beginIndex is negative, or endIndex is larger than the length of this String, or beginIndex is larger than endIndex.
since
1.5

	if (beginIndex < 0 || endIndex > count || beginIndex > endIndex) {
	    throw new IndexOutOfBoundsException();
	}
	return Character.codePointCountImpl(value, offset+beginIndex, endIndex-beginIndex);
    
public intcompareTo(java.lang.String anotherString)
Compares two strings lexicographically. The comparison is based on the Unicode value of each character in the strings. The character sequence represented by this String object is compared lexicographically to the character sequence represented by the argument string. The result is a negative integer if this String object lexicographically precedes the argument string. The result is a positive integer if this String object lexicographically follows the argument string. The result is zero if the strings are equal; compareTo returns 0 exactly when the {@link #equals(Object)} method would return true.

This is the definition of lexicographic ordering. If two strings are different, then either they have different characters at some index that is a valid index for both strings, or their lengths are different, or both. If they have different characters at one or more index positions, let k be the smallest such index; then the string whose character at position k has the smaller value, as determined by using the < operator, lexicographically precedes the other string. In this case, compareTo returns the difference of the two character values at position k in the two string -- that is, the value:

this.charAt(k)-anotherString.charAt(k)
If there is no index position at which they differ, then the shorter string lexicographically precedes the longer string. In this case, compareTo returns the difference of the lengths of the strings -- that is, the value:
this.length()-anotherString.length()

param
anotherString the String to be compared.
return
the value 0 if the argument string is equal to this string; a value less than 0 if this string is lexicographically less than the string argument; and a value greater than 0 if this string is lexicographically greater than the string argument.

	int len1 = count;
	int len2 = anotherString.count;
	int n = Math.min(len1, len2);
	char v1[] = value;
	char v2[] = anotherString.value;
	int i = offset;
	int j = anotherString.offset;

	if (i == j) {
	    int k = i;
	    int lim = n + i;
	    while (k < lim) {
		char c1 = v1[k];
		char c2 = v2[k];
		if (c1 != c2) {
		    return c1 - c2;
		}
		k++;
	    }
	} else {
	    while (n-- != 0) {
		char c1 = v1[i++];
		char c2 = v2[j++];
		if (c1 != c2) {
		    return c1 - c2;
		}
	    }
	}
	return len1 - len2;
    
public intcompareToIgnoreCase(java.lang.String str)
Compares two strings lexicographically, ignoring case differences. This method returns an integer whose sign is that of calling compareTo with normalized versions of the strings where case differences have been eliminated by calling Character.toLowerCase(Character.toUpperCase(character)) on each character.

Note that this method does not take locale into account, and will result in an unsatisfactory ordering for certain locales. The java.text package provides collators to allow locale-sensitive ordering.

param
str the String to be compared.
return
a negative integer, zero, or a positive integer as the specified String is greater than, equal to, or less than this String, ignoring case considerations.
see
java.text.Collator#compare(String, String)
since
1.2

        return CASE_INSENSITIVE_ORDER.compare(this, str);
    
public java.lang.Stringconcat(java.lang.String str)
Concatenates the specified string to the end of this string.

If the length of the argument string is 0, then this String object is returned. Otherwise, a new String object is created, representing a character sequence that is the concatenation of the character sequence represented by this String object and the character sequence represented by the argument string.

Examples:

"cares".concat("s") returns "caress"
"to".concat("get").concat("her") returns "together"

param
str the String that is concatenated to the end of this String.
return
a string that represents the concatenation of this object's characters followed by the string argument's characters.

	int otherLen = str.length();
	if (otherLen == 0) {
	    return this;
	}
	char buf[] = new char[count + otherLen];
	getChars(0, count, buf, 0);
	str.getChars(0, otherLen, buf, count);
	return new String(0, count + otherLen, buf);
    
public booleancontains(java.lang.CharSequence s)
Returns true if and only if this string contains the specified sequence of char values.

param
s the sequence to search for
return
true if this string contains s, false otherwise
throws
NullPointerException if s is null
since
1.5

        return indexOf(s.toString()) > -1;
    
public booleancontentEquals(java.lang.StringBuffer sb)
Returns true if and only if this String represents the same sequence of characters as the specified StringBuffer.

param
sb the StringBuffer to compare to.
return
true if and only if this String represents the same sequence of characters as the specified StringBuffer, otherwise false.
throws
NullPointerException if sb is null
since
1.4

        synchronized(sb) {
            return contentEquals((CharSequence)sb);
        }
    
public booleancontentEquals(java.lang.CharSequence cs)
Returns true if and only if this String represents the same sequence of char values as the specified sequence.

param
cs the sequence to compare to.
return
true if and only if this String represents the same sequence of char values as the specified sequence, otherwise false.
throws
NullPointerException if cs is null
since
1.5

        if (count != cs.length())
            return false;
        // Argument is a StringBuffer, StringBuilder
        if (cs instanceof AbstractStringBuilder) {
            char v1[] = value;
            char v2[] = ((AbstractStringBuilder)cs).getValue();
            int i = offset;
            int j = 0;
            int n = count;
            while (n-- != 0) {
                if (v1[i++] != v2[j++])
                    return false;
            }
        }
        // Argument is a String
        if (cs.equals(this))
            return true;
        // Argument is a generic CharSequence
        char v1[] = value;
        int i = offset;
        int j = 0;
        int n = count;
        while (n-- != 0) {
            if (v1[i++] != cs.charAt(j++))
                return false;
        }
        return true;
    
public static java.lang.StringcopyValueOf(char[] data, int offset, int count)
Returns a String that represents the character sequence in the array specified.

param
data the character array.
param
offset initial offset of the subarray.
param
count length of the subarray.
return
a String that contains the characters of the specified subarray of the character array.

	// All public String constructors now copy the data.
	return new String(data, offset, count);
    
public static java.lang.StringcopyValueOf(char[] data)
Returns a String that represents the character sequence in the array specified.

param
data the character array.
return
a String that contains the characters of the character array.

	return copyValueOf(data, 0, data.length);
    
public booleanendsWith(java.lang.String suffix)
Tests if this string ends with the specified suffix.

param
suffix the suffix.
return
true if the character sequence represented by the argument is a suffix of the character sequence represented by this object; false otherwise. Note that the result will be true if the argument is the empty string or is equal to this String object as determined by the {@link #equals(Object)} method.

	return startsWith(suffix, count - suffix.count);
    
public booleanequals(java.lang.Object anObject)
Compares this string to the specified object. The result is true if and only if the argument is not null and is a String object that represents the same sequence of characters as this object.

param
anObject the object to compare this String against.
return
true if the String are equal; false otherwise.
see
java.lang.String#compareTo(java.lang.String)
see
java.lang.String#equalsIgnoreCase(java.lang.String)

	if (this == anObject) {
	    return true;
	}
	if (anObject instanceof String) {
	    String anotherString = (String)anObject;
	    int n = count;
	    if (n == anotherString.count) {
		char v1[] = value;
		char v2[] = anotherString.value;
		int i = offset;
		int j = anotherString.offset;
		while (n-- != 0) {
		    if (v1[i++] != v2[j++])
			return false;
		}
		return true;
	    }
	}
	return false;
    
public booleanequalsIgnoreCase(java.lang.String anotherString)
Compares this String to another String, ignoring case considerations. Two strings are considered equal ignoring case if they are of the same length, and corresponding characters in the two strings are equal ignoring case.

Two characters c1 and c2 are considered the same, ignoring case if at least one of the following is true:

  • The two characters are the same (as compared by the == operator).
  • Applying the method {@link java.lang.Character#toUpperCase(char)} to each character produces the same result.
  • Applying the method {@link java.lang.Character#toLowerCase(char)} to each character produces the same result.

param
anotherString the String to compare this String against.
return
true if the argument is not null and the Strings are equal, ignoring case; false otherwise.
see
#equals(Object)
see
java.lang.Character#toLowerCase(char)
see
java.lang.Character#toUpperCase(char)

        return (this == anotherString) ? true :
               (anotherString != null) && (anotherString.count == count) &&
	       regionMatches(true, 0, anotherString, 0, count);
    
public static java.lang.Stringformat(java.lang.String format, java.lang.Object args)
Returns a formatted string using the specified format string and arguments.

The locale always used is the one returned by {@link java.util.Locale#getDefault() Locale.getDefault()}.

param
format A format string
param
args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
throws
IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
throws
NullPointerException If the format is null
return
A formatted string
see
java.util.Formatter
since
1.5

	return new Formatter().format(format, args).toString(); 
    
public static java.lang.Stringformat(java.util.Locale l, java.lang.String format, java.lang.Object args)
Returns a formatted string using the specified locale, format string, and arguments.

param
l The {@linkplain java.util.Locale locale} to apply during formatting. If l is null then no localization is applied.
param
format A format string
param
args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
throws
IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification
throws
NullPointerException If the format is null
return
A formatted string
see
java.util.Formatter
since
1.5

	return new Formatter(l).format(format, args).toString(); 
    
public voidgetBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin)
Copies characters from this string into the destination byte array. Each byte receives the 8 low-order bits of the corresponding character. The eight high-order bits of each character are not copied and do not participate in the transfer in any way.

The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1. The total number of characters to be copied is srcEnd-srcBegin. The characters, converted to bytes, are copied into the subarray of dst starting at index dstBegin and ending at index:

dstbegin + (srcEnd-srcBegin) - 1

deprecated
This method does not properly convert characters into bytes. As of JDK 1.1, the preferred way to do this is via the getBytes() method, which uses the platform's default charset.
param
srcBegin index of the first character in the string to copy.
param
srcEnd index after the last character in the string to copy.
param
dst the destination array.
param
dstBegin the start offset in the destination array.
exception
IndexOutOfBoundsException if any of the following is true:
  • srcBegin is negative
  • srcBegin is greater than srcEnd
  • srcEnd is greater than the length of this String
  • dstBegin is negative
  • dstBegin+(srcEnd-srcBegin) is larger than dst.length

        if (srcBegin < 0) {
            throw new StringIndexOutOfBoundsException(srcBegin);
        }
        if (srcEnd > count) {
            throw new StringIndexOutOfBoundsException(srcEnd);
        }
        if (srcBegin > srcEnd) {
            throw new StringIndexOutOfBoundsException(srcEnd - srcBegin);
        }
        int j = dstBegin;
        int n = offset + srcEnd;
        int i = offset + srcBegin;
        char[] val = value;   /* avoid getfield opcode */

        while (i < n) {
            dst[j++] = (byte)val[i++];
        }
    
public byte[]getBytes(java.lang.String charsetName)
Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.

The behavior of this method when this string cannot be encoded in the given charset is unspecified. The {@link java.nio.charset.CharsetEncoder} class should be used when more control over the encoding process is required.

param
charsetName the name of a supported {@link java.nio.charset.Charset charset}
return
The resultant byte array
exception
UnsupportedEncodingException If the named charset is not supported
since
JDK1.1

	if (charsetName == null) throw new NullPointerException();
	return StringCoding.encode(charsetName, value, offset, count);
    
public byte[]getBytes()
Encodes this String into a sequence of bytes using the platform's default charset, storing the result into a new byte array.

The behavior of this method when this string cannot be encoded in the default charset is unspecified. The {@link java.nio.charset.CharsetEncoder} class should be used when more control over the encoding process is required.

return
The resultant byte array
since
JDK1.1

	return StringCoding.encode(value, offset, count);
    
voidgetChars(char[] dst, int dstBegin)
Copy characters from this string into dst starting at dstBegin. This method doesn't perform any range checking.

        System.arraycopy(value, offset, dst, dstBegin, count);
    
public voidgetChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)
Copies characters from this string into the destination character array.

The first character to be copied is at index srcBegin; the last character to be copied is at index srcEnd-1 (thus the total number of characters to be copied is srcEnd-srcBegin). The characters are copied into the subarray of dst starting at index dstBegin and ending at index:

dstbegin + (srcEnd-srcBegin) - 1

param
srcBegin index of the first character in the string to copy.
param
srcEnd index after the last character in the string to copy.
param
dst the destination array.
param
dstBegin the start offset in the destination array.
exception
IndexOutOfBoundsException If any of the following is true:
  • srcBegin is negative.
  • srcBegin is greater than srcEnd
  • srcEnd is greater than the length of this string
  • dstBegin is negative
  • dstBegin+(srcEnd-srcBegin) is larger than dst.length

        if (srcBegin < 0) {
            throw new StringIndexOutOfBoundsException(srcBegin);
        }
        if (srcEnd > count) {
            throw new StringIndexOutOfBoundsException(srcEnd);
        }
        if (srcBegin > srcEnd) {
            throw new StringIndexOutOfBoundsException(srcEnd - srcBegin);
        }
        System.arraycopy(value, offset + srcBegin, dst, dstBegin,
             srcEnd - srcBegin);
    
public inthashCode()
Returns a hash code for this string. The hash code for a String object is computed as
s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]
using int arithmetic, where s[i] is the ith character of the string, n is the length of the string, and ^ indicates exponentiation. (The hash value of the empty string is zero.)

return
a hash code value for this object.

	int h = hash;
	if (h == 0) {
	    int off = offset;
	    char val[] = value;
	    int len = count;

            for (int i = 0; i < len; i++) {
                h = 31*h + val[off++];
            }
            hash = h;
        }
        return h;
    
public intindexOf(int ch)
Returns the index within this string of the first occurrence of the specified character. If a character with value ch occurs in the character sequence represented by this String object, then the index (in Unicode code units) of the first such occurrence is returned. For values of ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:
this.charAt(k) == ch
is true. For other values of ch, it is the smallest value k such that:
this.codePointAt(k) == ch
is true. In either case, if no such character occurs in this string, then -1 is returned.

param
ch a character (Unicode code point).
return
the index of the first occurrence of the character in the character sequence represented by this object, or -1 if the character does not occur.

	return indexOf(ch, 0);
    
public intindexOf(int ch, int fromIndex)
Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.

If a character with value ch occurs in the character sequence represented by this String object at an index no smaller than fromIndex, then the index of the first such occurrence is returned. For values of ch in the range from 0 to 0xFFFF (inclusive), this is the smallest value k such that:

(this.charAt(k) == ch) && (k >= fromIndex)
is true. For other values of ch, it is the smallest value k such that:
(this.codePointAt(k) == ch) && (k >= fromIndex)
is true. In either case, if no such character occurs in this string at or after position fromIndex, then -1 is returned.

There is no restriction on the value of fromIndex. If it is negative, it has the same effect as if it were zero: this entire string may be searched. If it is greater than the length of this string, it has the same effect as if it were equal to the length of this string: -1 is returned.

All indices are specified in char values (Unicode code units).

param
ch a character (Unicode code point).
param
fromIndex the index to start the search from.
return
the index of the first occurrence of the character in the character sequence represented by this object that is greater than or equal to fromIndex, or -1 if the character does not occur.

	int max = offset + count;
	char v[] = value;

	if (fromIndex < 0) {
	    fromIndex = 0;
	} else if (fromIndex >= count) {
	    // Note: fromIndex might be near -1>>>1.
	    return -1;
	}

	int i = offset + fromIndex;
	if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
	    // handle most cases here (ch is a BMP code point or a
	    // negative value (invalid code point))
	    for (; i < max ; i++) {
		if (v[i] == ch) {
		    return i - offset;
		}
	    }
	    return -1;
	}

	if (ch <= Character.MAX_CODE_POINT) {
	    // handle supplementary characters here
	    char[] surrogates = Character.toChars(ch);
	    for (; i < max; i++) {
		if (v[i] == surrogates[0]) {
		    if (i + 1 == max) {
			break;
		    }
		    if (v[i+1] == surrogates[1]) {
			return i - offset;
		    }
		}
	    }
	}
	return -1;
    
public intindexOf(java.lang.String str)
Returns the index within this string of the first occurrence of the specified substring. The integer returned is the smallest value k such that:
this.startsWith(str, k)
is true.

param
str any string.
return
if the string argument occurs as a substring within this object, then the index of the first character of the first such substring is returned; if it does not occur as a substring, -1 is returned.

	return indexOf(str, 0);
    
public intindexOf(java.lang.String str, int fromIndex)
Returns the index within this string of the first occurrence of the specified substring, starting at the specified index. The integer returned is the smallest value k for which:
k >= Math.min(fromIndex, str.length()) && this.startsWith(str, k)
If no such value of k exists, then -1 is returned.

param
str the substring for which to search.
param
fromIndex the index from which to start the search.
return
the index within this string of the first occurrence of the specified substring, starting at the specified index.

        return indexOf(value, offset, count,
                       str.value, str.offset, str.count, fromIndex);
    
static intindexOf(char[] source, int sourceOffset, int sourceCount, char[] target, int targetOffset, int targetCount, int fromIndex)
Code shared by String and StringBuffer to do searches. The source is the character array being searched, and the target is the string being searched for.

param
source the characters being searched.
param
sourceOffset offset of the source string.
param
sourceCount count of the source string.
param
target the characters being searched for.
param
targetOffset offset of the target string.
param
targetCount count of the target string.
param
fromIndex the index to begin searching from.

	if (fromIndex >= sourceCount) {
            return (targetCount == 0 ? sourceCount : -1);
	}
    	if (fromIndex < 0) {
    	    fromIndex = 0;
    	}
	if (targetCount == 0) {
	    return fromIndex;
	}

        char first  = target[targetOffset];
        int max = sourceOffset + (sourceCount - targetCount);

        for (int i = sourceOffset + fromIndex; i <= max; i++) {
            /* Look for first character. */
            if (source[i] != first) {
                while (++i <= max && source[i] != first);
            }

            /* Found first character, now look at the rest of v2 */
            if (i <= max) {
                int j = i + 1;
                int end = j + targetCount - 1;
                for (int k = targetOffset + 1; j < end && source[j] == 
                         target[k]; j++, k++);

                if (j == end) {
                    /* Found whole string. */
                    return i - sourceOffset;
                }
            }
        }
        return -1;
    
public native java.lang.Stringintern()
Returns a canonical representation for the string object.

A pool of strings, initially empty, is maintained privately by the class String.

When the intern method is invoked, if the pool already contains a string equal to this String object as determined by the {@link #equals(Object)} method, then the string from the pool is returned. Otherwise, this String object is added to the pool and a reference to this String object is returned.

It follows that for any two strings s and t, s.intern() == t.intern() is true if and only if s.equals(t) is true.

All literal strings and string-valued constant expressions are interned. String literals are defined in §3.10.5 of the Java Language Specification

return
a string that has the same contents as this string, but is guaranteed to be from a pool of unique strings.

public intlastIndexOf(int ch)
Returns the index within this string of the last occurrence of the specified character. For values of ch in the range from 0 to 0xFFFF (inclusive), the index (in Unicode code units) returned is the largest value k such that:
this.charAt(k) == ch
is true. For other values of ch, it is the largest value k such that:
this.codePointAt(k) == ch
is true. In either case, if no such character occurs in this string, then -1 is returned. The String is searched backwards starting at the last character.

param
ch a character (Unicode code point).
return
the index of the last occurrence of the character in the character sequence represented by this object, or -1 if the character does not occur.

	return lastIndexOf(ch, count - 1);
    
public intlastIndexOf(int ch, int fromIndex)
Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index. For values of ch in the range from 0 to 0xFFFF (inclusive), the index returned is the largest value k such that:
(this.charAt(k) == ch) && (k <= fromIndex)
is true. For other values of ch, it is the largest value k such that:
(this.codePointAt(k) == ch) && (k <= fromIndex)
is true. In either case, if no such character occurs in this string at or before position fromIndex, then -1 is returned.

All indices are specified in char values (Unicode code units).

param
ch a character (Unicode code point).
param
fromIndex the index to start the search from. There is no restriction on the value of fromIndex. If it is greater than or equal to the length of this string, it has the same effect as if it were equal to one less than the length of this string: this entire string may be searched. If it is negative, it has the same effect as if it were -1: -1 is returned.
return
the index of the last occurrence of the character in the character sequence represented by this object that is less than or equal to fromIndex, or -1 if the character does not occur before that point.

	int min = offset;
	char v[] = value;

	int i = offset + ((fromIndex >= count) ? count - 1 : fromIndex);

	if (ch < Character.MIN_SUPPLEMENTARY_CODE_POINT) {
	    // handle most cases here (ch is a BMP code point or a
	    // negative value (invalid code point))
	    for (; i >= min ; i--) {
		if (v[i] == ch) {
		    return i - offset;
		}
	    }
	    return -1;
	}

	int max = offset + count;
	if (ch <= Character.MAX_CODE_POINT) {
	    // handle supplementary characters here
	    char[] surrogates = Character.toChars(ch);
	    for (; i >= min; i--) {
		if (v[i] == surrogates[0]) {
		    if (i + 1 == max) {
			break;
		    }
		    if (v[i+1] == surrogates[1]) {
			return i - offset;
		    }
		}
	    }
	}
	return -1;
    
public intlastIndexOf(java.lang.String str)
Returns the index within this string of the rightmost occurrence of the specified substring. The rightmost empty string "" is considered to occur at the index value this.length(). The returned index is the largest value k such that
this.startsWith(str, k)
is true.

param
str the substring to search for.
return
if the string argument occurs one or more times as a substring within this object, then the index of the first character of the last such substring is returned. If it does not occur as a substring, -1 is returned.

	return lastIndexOf(str, count);
    
public intlastIndexOf(java.lang.String str, int fromIndex)
Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index. The integer returned is the largest value k such that:
k <= Math.min(fromIndex, str.length()) && this.startsWith(str, k)
If no such value of k exists, then -1 is returned.

param
str the substring to search for.
param
fromIndex the index to start the search from.
return
the index within this string of the last occurrence of the specified substring.

        return lastIndexOf(value, offset, count,
                           str.value, str.offset, str.count, fromIndex);
    
static intlastIndexOf(char[] source, int sourceOffset, int sourceCount, char[] target, int targetOffset, int targetCount, int fromIndex)
Code shared by String and StringBuffer to do searches. The source is the character array being searched, and the target is the string being searched for.

param
source the characters being searched.
param
sourceOffset offset of the source string.
param
sourceCount count of the source string.
param
target the characters being searched for.
param
targetOffset offset of the target string.
param
targetCount count of the target string.
param
fromIndex the index to begin searching from.

        /*
	 * Check arguments; return immediately where possible. For
	 * consistency, don't check for null str.
	 */
        int rightIndex = sourceCount - targetCount;
	if (fromIndex < 0) {
	    return -1;
	}
	if (fromIndex > rightIndex) {
	    fromIndex = rightIndex;
	}
	/* Empty string always matches. */
	if (targetCount == 0) {
	    return fromIndex;
	}

        int strLastIndex = targetOffset + targetCount - 1;
	char strLastChar = target[strLastIndex];
	int min = sourceOffset + targetCount - 1;
	int i = min + fromIndex;

    startSearchForLastChar:
	while (true) {
	    while (i >= min && source[i] != strLastChar) {
		i--;
	    }
	    if (i < min) {
		return -1;
	    }
	    int j = i - 1;
	    int start = j - (targetCount - 1);
	    int k = strLastIndex - 1;

	    while (j > start) {
	        if (source[j--] != target[k--]) {
		    i--;
		    continue startSearchForLastChar;
		}
	    }
	    return start - sourceOffset + 1;
	}
    
public intlength()
Returns the length of this string. The length is equal to the number of 16-bit Unicode characters in the string.

return
the length of the sequence of characters represented by this object.

        return count;
    
public booleanmatches(java.lang.String regex)
Tells whether or not this string matches the given regular expression.

An invocation of this method of the form str.matches(regex) yields exactly the same result as the expression

{@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#matches(String,CharSequence) matches}(regex, str)

param
regex the regular expression to which this string is to be matched
return
true if, and only if, this string matches the given regular expression
throws
PatternSyntaxException if the regular expression's syntax is invalid
see
java.util.regex.Pattern
since
1.4
spec
JSR-51

        return Pattern.matches(regex, this);
    
public intoffsetByCodePoints(int index, int codePointOffset)
Returns the index within this String that is offset from the given index by codePointOffset code points. Unpaired surrogates within the text range given by index and codePointOffset count as one code point each.

param
index the index to be offset
param
codePointOffset the offset in code points
return
the index within this String
exception
IndexOutOfBoundsException if index is negative or larger then the length of this String, or if codePointOffset is positive and the substring starting with index has fewer than codePointOffset code points, or if codePointOffset is negative and the substring before index has fewer than the absolute value of codePointOffset code points.
since
1.5

	if (index < 0 || index > count) {
	    throw new IndexOutOfBoundsException();
	}
	return Character.offsetByCodePointsImpl(value, offset, count,
						offset+index, codePointOffset);
    
public booleanregionMatches(int toffset, java.lang.String other, int ooffset, int len)
Tests if two string regions are equal.

A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent identical character sequences. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is false if and only if at least one of the following is true:

  • toffset is negative.
  • ooffset is negative.
  • toffset+len is greater than the length of this String object.
  • ooffset+len is greater than the length of the other argument.
  • There is some nonnegative integer k less than len such that: this.charAt(toffset+k) != other.charAt(ooffset+k)

param
toffset the starting offset of the subregion in this string.
param
other the string argument.
param
ooffset the starting offset of the subregion in the string argument.
param
len the number of characters to compare.
return
true if the specified subregion of this string exactly matches the specified subregion of the string argument; false otherwise.

	char ta[] = value;
	int to = offset + toffset;
	char pa[] = other.value;
	int po = other.offset + ooffset;
	// Note: toffset, ooffset, or len might be near -1>>>1.
	if ((ooffset < 0) || (toffset < 0) || (toffset > (long)count - len)
	    || (ooffset > (long)other.count - len)) {
	    return false;
	}
	while (len-- > 0) {
	    if (ta[to++] != pa[po++]) {
	        return false;
	    }
	}
	return true;
    
public booleanregionMatches(boolean ignoreCase, int toffset, java.lang.String other, int ooffset, int len)
Tests if two string regions are equal.

A substring of this String object is compared to a substring of the argument other. The result is true if these substrings represent character sequences that are the same, ignoring case if and only if ignoreCase is true. The substring of this String object to be compared begins at index toffset and has length len. The substring of other to be compared begins at index ooffset and has length len. The result is false if and only if at least one of the following is true:

  • toffset is negative.
  • ooffset is negative.
  • toffset+len is greater than the length of this String object.
  • ooffset+len is greater than the length of the other argument.
  • ignoreCase is false and there is some nonnegative integer k less than len such that:
    this.charAt(toffset+k) != other.charAt(ooffset+k)
    
  • ignoreCase is true and there is some nonnegative integer k less than len such that:
    Character.toLowerCase(this.charAt(toffset+k)) !=
    Character.toLowerCase(other.charAt(ooffset+k))
    
    and:
    Character.toUpperCase(this.charAt(toffset+k)) !=
    Character.toUpperCase(other.charAt(ooffset+k))
    

param
ignoreCase if true, ignore case when comparing characters.
param
toffset the starting offset of the subregion in this string.
param
other the string argument.
param
ooffset the starting offset of the subregion in the string argument.
param
len the number of characters to compare.
return
true if the specified subregion of this string matches the specified subregion of the string argument; false otherwise. Whether the matching is exact or case insensitive depends on the ignoreCase argument.

        char ta[] = value;
        int to = offset + toffset;
        char pa[] = other.value;
        int po = other.offset + ooffset;
        // Note: toffset, ooffset, or len might be near -1>>>1.
        if ((ooffset < 0) || (toffset < 0) || (toffset > (long)count - len) ||
                (ooffset > (long)other.count - len)) {
            return false;
        }
        while (len-- > 0) {
            char c1 = ta[to++];
            char c2 = pa[po++];
            if (c1 == c2) {
                continue;
            }
            if (ignoreCase) {
                // If characters don't match but case may be ignored,
                // try converting both characters to uppercase.
                // If the results match, then the comparison scan should
                // continue.
                char u1 = Character.toUpperCase(c1);
                char u2 = Character.toUpperCase(c2);
                if (u1 == u2) {
                    continue;
                }
                // Unfortunately, conversion to uppercase does not work properly
                // for the Georgian alphabet, which has strange rules about case
                // conversion.  So we need to make one last check before
                // exiting.
                if (Character.toLowerCase(u1) == Character.toLowerCase(u2)) {
                    continue;
                }
            }
            return false;
        }
        return true;
    
public java.lang.Stringreplace(char oldChar, char newChar)
Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.

If the character oldChar does not occur in the character sequence represented by this String object, then a reference to this String object is returned. Otherwise, a new String object is created that represents a character sequence identical to the character sequence represented by this String object, except that every occurrence of oldChar is replaced by an occurrence of newChar.

Examples:

"mesquite in your cellar".replace('e', 'o')
returns "mosquito in your collar"
"the war of baronets".replace('r', 'y')
returns "the way of bayonets"
"sparring with a purple porpoise".replace('p', 't')
returns "starring with a turtle tortoise"
"JonL".replace('q', 'x') returns "JonL" (no change)

param
oldChar the old character.
param
newChar the new character.
return
a string derived from this string by replacing every occurrence of oldChar with newChar.

	if (oldChar != newChar) {
	    int len = count;
	    int i = -1;
	    char[] val = value; /* avoid getfield opcode */
	    int off = offset;   /* avoid getfield opcode */

	    while (++i < len) {
		if (val[off + i] == oldChar) {
		    break;
		}
	    }
	    if (i < len) {
		char buf[] = new char[len];
		for (int j = 0 ; j < i ; j++) {
		    buf[j] = val[off+j];
		}
		while (i < len) {
		    char c = val[off + i];
		    buf[i] = (c == oldChar) ? newChar : c;
		    i++;
		}
		return new String(0, len, buf);
	    }
	}
	return this;
    
public java.lang.Stringreplace(java.lang.CharSequence target, java.lang.CharSequence replacement)
Replaces each substring of this string that matches the literal target sequence with the specified literal replacement sequence. The replacement proceeds from the beginning of the string to the end, for example, replacing "aa" with "b" in the string "aaa" will result in "ba" rather than "ab".

param
target The sequence of char values to be replaced
param
replacement The replacement sequence of char values
return
The resulting string
throws
NullPointerException if target or replacement is null.
since
1.5

        return Pattern.compile(target.toString(), Pattern.LITERAL).matcher(
            this).replaceAll(Matcher.quoteReplacement(replacement.toString()));
    
public java.lang.StringreplaceAll(java.lang.String regex, java.lang.String replacement)
Replaces each substring of this string that matches the given regular expression with the given replacement.

An invocation of this method of the form str.replaceAll(regex, repl) yields exactly the same result as the expression

{@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile compile}(regex).{@link java.util.regex.Pattern#matcher(java.lang.CharSequence) matcher}(str).{@link java.util.regex.Matcher#replaceAll replaceAll}(repl)

param
regex the regular expression to which this string is to be matched
return
The resulting String
throws
PatternSyntaxException if the regular expression's syntax is invalid
see
java.util.regex.Pattern
since
1.4
spec
JSR-51

	return Pattern.compile(regex).matcher(this).replaceAll(replacement);
    
public java.lang.StringreplaceFirst(java.lang.String regex, java.lang.String replacement)
Replaces the first substring of this string that matches the given regular expression with the given replacement.

An invocation of this method of the form str.replaceFirst(regex, repl) yields exactly the same result as the expression

{@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile compile}(regex).{@link java.util.regex.Pattern#matcher(java.lang.CharSequence) matcher}(str).{@link java.util.regex.Matcher#replaceFirst replaceFirst}(repl)

param
regex the regular expression to which this string is to be matched
return
The resulting String
throws
PatternSyntaxException if the regular expression's syntax is invalid
see
java.util.regex.Pattern
since
1.4
spec
JSR-51

	return Pattern.compile(regex).matcher(this).replaceFirst(replacement);
    
public java.lang.String[]split(java.lang.String regex, int limit)
Splits this string around matches of the given regular expression.

The array returned by this method contains each substring of this string that is terminated by another substring that matches the given expression or is terminated by the end of the string. The substrings in the array are in the order in which they occur in this string. If the expression does not match any part of the input then the resulting array has just one element, namely this string.

The limit parameter controls the number of times the pattern is applied and therefore affects the length of the resulting array. If the limit n is greater than zero then the pattern will be applied at most n - 1 times, the array's length will be no greater than n, and the array's last entry will contain all input beyond the last matched delimiter. If n is non-positive then the pattern will be applied as many times as possible and the array can have any length. If n is zero then the pattern will be applied as many times as possible, the array can have any length, and trailing empty strings will be discarded.

The string "boo:and:foo", for example, yields the following results with these parameters:

Regex Limit Result
: 2 { "boo", "and:foo" }
: 5 { "boo", "and", "foo" }
: -2 { "boo", "and", "foo" }
o 5 { "b", "", ":and:f", "", "" }
o -2 { "b", "", ":and:f", "", "" }
o 0 { "b", "", ":and:f" }

An invocation of this method of the form str.split(regex, n) yields the same result as the expression

{@link java.util.regex.Pattern}.{@link java.util.regex.Pattern#compile compile}(regex).{@link java.util.regex.Pattern#split(java.lang.CharSequence,int) split}(str, n)

param
regex the delimiting regular expression
param
limit the result threshold, as described above
return
the array of strings computed by splitting this string around matches of the given regular expression
throws
PatternSyntaxException if the regular expression's syntax is invalid
see
java.util.regex.Pattern
since
1.4
spec
JSR-51

	return Pattern.compile(regex).split(this, limit);
    
public java.lang.String[]split(java.lang.String regex)
Splits this string around matches of the given {@linkplain java.util.regex.Pattern#sum regular expression}.

This method works as if by invoking the two-argument {@link #split(String, int) split} method with the given expression and a limit argument of zero. Trailing empty strings are therefore not included in the resulting array.

The string "boo:and:foo", for example, yields the following results with these expressions:

Regex Result
: { "boo", "and", "foo" }
o { "b", "", ":and:f" }

param
regex the delimiting regular expression
return
the array of strings computed by splitting this string around matches of the given regular expression
throws
PatternSyntaxException if the regular expression's syntax is invalid
see
java.util.regex.Pattern
since
1.4
spec
JSR-51

        return split(regex, 0);
    
public booleanstartsWith(java.lang.String prefix, int toffset)
Tests if this string starts with the specified prefix beginning a specified index.

param
prefix the prefix.
param
toffset where to begin looking in the string.
return
true if the character sequence represented by the argument is a prefix of the substring of this object starting at index toffset; false otherwise. The result is false if toffset is negative or greater than the length of this String object; otherwise the result is the same as the result of the expression
this.substring(toffset).startsWith(prefix)

	char ta[] = value;
	int to = offset + toffset;
	char pa[] = prefix.value;
	int po = prefix.offset;
	int pc = prefix.count;
	// Note: toffset might be near -1>>>1.
	if ((toffset < 0) || (toffset > count - pc)) {
	    return false;
	}
	while (--pc >= 0) {
	    if (ta[to++] != pa[po++]) {
	        return false;
	    }
	}
	return true;
    
public booleanstartsWith(java.lang.String prefix)
Tests if this string starts with the specified prefix.

param
prefix the prefix.
return
true if the character sequence represented by the argument is a prefix of the character sequence represented by this string; false otherwise. Note also that true will be returned if the argument is an empty string or is equal to this String object as determined by the {@link #equals(Object)} method.
since
1. 0

	return startsWith(prefix, 0);
    
public java.lang.CharSequencesubSequence(int beginIndex, int endIndex)
Returns a new character sequence that is a subsequence of this sequence.

An invocation of this method of the form

str.subSequence(begin, end)
behaves in exactly the same way as the invocation
str.substring(begin, end)
This method is defined so that the String class can implement the {@link CharSequence} interface.

param
beginIndex the begin index, inclusive.
param
endIndex the end index, exclusive.
return
the specified subsequence.
throws
IndexOutOfBoundsException if beginIndex or endIndex are negative, if endIndex is greater than length(), or if beginIndex is greater than startIndex
since
1.4
spec
JSR-51

        return this.substring(beginIndex, endIndex);
    
public java.lang.Stringsubstring(int beginIndex)
Returns a new string that is a substring of this string. The substring begins with the character at the specified index and extends to the end of this string.

Examples:

"unhappy".substring(2) returns "happy"
"Harbison".substring(3) returns "bison"
"emptiness".substring(9) returns "" (an empty string)

param
beginIndex the beginning index, inclusive.
return
the specified substring.
exception
IndexOutOfBoundsException if beginIndex is negative or larger than the length of this String object.

	return substring(beginIndex, count);
    
public java.lang.Stringsubstring(int beginIndex, int endIndex)
Returns a new string that is a substring of this string. The substring begins at the specified beginIndex and extends to the character at index endIndex - 1. Thus the length of the substring is endIndex-beginIndex.

Examples:

"hamburger".substring(4, 8) returns "urge"
"smiles".substring(1, 5) returns "mile"

param
beginIndex the beginning index, inclusive.
param
endIndex the ending index, exclusive.
return
the specified substring.
exception
IndexOutOfBoundsException if the beginIndex is negative, or endIndex is larger than the length of this String object, or beginIndex is larger than endIndex.

	if (beginIndex < 0) {
	    throw new StringIndexOutOfBoundsException(beginIndex);
	}
	if (endIndex > count) {
	    throw new StringIndexOutOfBoundsException(endIndex);
	}
	if (beginIndex > endIndex) {
	    throw new StringIndexOutOfBoundsException(endIndex - beginIndex);
	}
	return ((beginIndex == 0) && (endIndex == count)) ? this :
	    new String(offset + beginIndex, endIndex - beginIndex, value);
    
public char[]toCharArray()
Converts this string to a new character array.

return
a newly allocated character array whose length is the length of this string and whose contents are initialized to contain the character sequence represented by this string.

	char result[] = new char[count];
	getChars(0, count, result, 0);
	return result;
    
public java.lang.StringtoLowerCase(java.util.Locale locale)
Converts all of the characters in this String to lower case using the rules of the given Locale. Case mapping is based on the Unicode Standard version specified by the {@link java.lang.Character Character} class. Since case mappings are not always 1:1 char mappings, the resulting String may be a different length than the original String.

Examples of lowercase mappings are in the following table:
Language Code of Locale Upper Case Lower Case Description
tr (Turkish) \u0130 \u0069 capital letter I with dot above -> small letter i
tr (Turkish) \u0049 \u0131 capital letter I -> small letter dotless i
(all) French Fries french fries lowercased all chars in String
(all) capiotacapchi capthetacapupsil capsigma iotachi thetaupsilon sigma lowercased all chars in String

param
locale use the case transformation rules for this locale
return
the String, converted to lowercase.
see
java.lang.String#toLowerCase()
see
java.lang.String#toUpperCase()
see
java.lang.String#toUpperCase(Locale)
since
1.1

	if (locale == null) {
	    throw new NullPointerException();
        }
	
        int     firstUpper;

	/* Now check if there are any characters that need to be changed. */
	scan: {
            int c;
	    for (firstUpper = 0 ;
                    firstUpper < count ; 
                    firstUpper += Character.charCount(c)) {
		c = codePointAt(firstUpper);
		if (c != Character.toLowerCase(c)) {
                    break scan;
                }
	    }
	    return this;
	}

        char[]  result = new char[count];
	int     resultOffset = 0;  /* result grows or shrinks, so i+resultOffset
				    * is the write location in result */

        /* Just copy the first few lowerCase characters. */
        System.arraycopy(value, offset, result, 0, firstUpper);

	String lang = locale.getLanguage().intern();
	boolean localeDependent = 
            (lang == "tr" || lang == "az" || lang == "lt");
        char[] lowerCharArray;
        int lowerChar;
        int srcChar;
        int srcCount;
        for (int i = firstUpper; i < count; i += srcCount) {
	    srcChar = codePointAt(i);
            srcCount = Character.charCount(srcChar);
            if (localeDependent || srcChar == '\u03A3") { // GREEK CAPITAL LETTER SIGMA
                lowerChar = ConditionalSpecialCasing.toLowerCaseEx(this, i, locale);
            } else {
                lowerChar = Character.toLowerCase(srcChar);
            }
            if ((lowerChar == Character.ERROR) ||
                    Character.isSupplementaryCodePoint(lowerChar)) {
                if (lowerChar == Character.ERROR) {
                    lowerCharArray =
                        ConditionalSpecialCasing.toLowerCaseCharArray(this, i, locale);
                } else {
                    lowerCharArray = Character.toChars(lowerChar);
                }
                /* Grow/Shrink result. */
                int mapLen = lowerCharArray.length;
                char[] result2 = new char[result.length + mapLen - srcCount];
                System.arraycopy(result, 0, result2, 0,
                    i + resultOffset);
                for (int x=0; x<mapLen; ++x) {
                    result2[i+resultOffset+x] = lowerCharArray[x];
                }
                resultOffset += (mapLen - srcCount);
                result = result2;
            } else {
                result[i+resultOffset] = (char)lowerChar;
            }
        }
        return new String(0, result.length, result);
    
public java.lang.StringtoLowerCase()
Converts all of the characters in this String to lower case using the rules of the default locale. This is equivalent to calling toLowerCase(Locale.getDefault()).

return
the String, converted to lowercase.
see
java.lang.String#toLowerCase(Locale)

        return toLowerCase(Locale.getDefault());
    
public java.lang.StringtoString()
This object (which is already a string!) is itself returned.

return
the string itself.

	return this;
    
public java.lang.StringtoUpperCase(java.util.Locale locale)
Converts all of the characters in this String to upper case using the rules of the given Locale. Case mapping is based on the Unicode Standard version specified by the {@link java.lang.Character Character} class. Since case mappings are not always 1:1 char mappings, the resulting String may be a different length than the original String.

Examples of locale-sensitive and 1:M case mappings are in the following table.

Language Code of Locale Lower Case Upper Case Description
tr (Turkish) \u0069 \u0130 small letter i -> capital letter I with dot above
tr (Turkish) \u0131 \u0049 small letter dotless i -> capital letter I
(all) \u00df \u0053 \u0053 small letter sharp s -> two letters: SS
(all) Fahrvergnügen FAHRVERGNÜGEN

param
locale use the case transformation rules for this locale
return
the String, converted to uppercase.
see
java.lang.String#toUpperCase()
see
java.lang.String#toLowerCase()
see
java.lang.String#toLowerCase(Locale)
since
1.1

	if (locale == null) {
	    throw new NullPointerException();
        }
        
        int     firstLower;

        /* Now check if there are any characters that need changing. */
        scan: {
            int c;
            for (firstLower = 0 ; 
                    firstLower < count; 
                    firstLower += Character.charCount(c)) {
		c = codePointAt(firstLower);
                int upperCaseChar = Character.toUpperCaseEx(c);
                if (upperCaseChar == Character.ERROR || c != upperCaseChar) {
                    break scan;
                }
            }
            return this;
        }

        char[]  result       = new char[count]; /* might grow or shrink! */
	int     resultOffset = 0;  /* result grows or shrinks, so i+resultOffset
				    * is the write location in result */

	/* Just copy the first few upperCase characters. */
	System.arraycopy(value, offset, result, 0, firstLower);

	String lang = locale.getLanguage().intern();
	boolean localeDependent = 
            (lang == "tr" || lang == "az" || lang == "lt");
        char[] upperCharArray;
        int upperChar;
        int srcChar;
        int srcCount;
        for (int i = firstLower; i < count; i += srcCount) {
	    srcChar = codePointAt(i);
            srcCount = Character.charCount(srcChar);
            if (localeDependent) {
                upperChar = ConditionalSpecialCasing.toUpperCaseEx(this, i, locale);
            } else {
                upperChar = Character.toUpperCaseEx(srcChar);
            }
            if ((upperChar == Character.ERROR) ||
                    Character.isSupplementaryCodePoint(upperChar)) {
                if (upperChar == Character.ERROR) {
                    if (localeDependent) {
                        upperCharArray =
                            ConditionalSpecialCasing.toUpperCaseCharArray(this, i, locale);
                    } else {
                        upperCharArray = Character.toUpperCaseCharArray(srcChar);
                    }
                } else {
                    upperCharArray = Character.toChars(upperChar);
                }
                /* Grow/Shrink result. */
                int mapLen = upperCharArray.length;
                char[] result2 = new char[result.length + mapLen - srcCount];
                System.arraycopy(result, 0, result2, 0,
                    i + resultOffset);
                for (int x=0; x<mapLen; ++x) {
                    result2[i+resultOffset+x] = upperCharArray[x];
                }
                resultOffset += (mapLen - srcCount);
                result = result2;
            } else {
                result[i+resultOffset] = (char)upperChar;
            }
        }
        return new String(0, result.length, result);
    
public java.lang.StringtoUpperCase()
Converts all of the characters in this String to upper case using the rules of the default locale. This method is equivalent to toUpperCase(Locale.getDefault()).

return
the String, converted to uppercase.
see
java.lang.String#toUpperCase(Locale)

        return toUpperCase(Locale.getDefault());
    
public java.lang.Stringtrim()
Returns a copy of the string, with leading and trailing whitespace omitted.

If this String object represents an empty character sequence, or the first and last characters of character sequence represented by this String object both have codes greater than '\u0020' (the space character), then a reference to this String object is returned.

Otherwise, if there is no character with a code greater than '\u0020' in the string, then a new String object representing an empty string is created and returned.

Otherwise, let k be the index of the first character in the string whose code is greater than '\u0020', and let m be the index of the last character in the string whose code is greater than '\u0020'. A new String object is created, representing the substring of this string that begins with the character at index k and ends with the character at index m-that is, the result of this.substring(km+1).

This method may be used to trim whitespace (as defined above) from the beginning and end of a string.

return
A copy of this string with leading and trailing white space removed, or this string if it has no leading or trailing white space.

	int len = count;
	int st = 0;
	int off = offset;      /* avoid getfield opcode */
	char[] val = value;    /* avoid getfield opcode */

	while ((st < len) && (val[off + st] <= ' ")) {
	    st++;
	}
	while ((st < len) && (val[off + len - 1] <= ' ")) {
	    len--;
	}
	return ((st > 0) || (len < count)) ? substring(st, len) : this;
    
public static java.lang.StringvalueOf(java.lang.Object obj)
Returns the string representation of the Object argument.

param
obj an Object.
return
if the argument is null, then a string equal to "null"; otherwise, the value of obj.toString() is returned.
see
java.lang.Object#toString()

	return (obj == null) ? "null" : obj.toString();
    
public static java.lang.StringvalueOf(char[] data)
Returns the string representation of the char array argument. The contents of the character array are copied; subsequent modification of the character array does not affect the newly created string.

param
data a char array.
return
a newly allocated string representing the same sequence of characters contained in the character array argument.

	return new String(data);
    
public static java.lang.StringvalueOf(char[] data, int offset, int count)
Returns the string representation of a specific subarray of the char array argument.

The offset argument is the index of the first character of the subarray. The count argument specifies the length of the subarray. The contents of the subarray are copied; subsequent modification of the character array does not affect the newly created string.

param
data the character array.
param
offset the initial offset into the value of the String.
param
count the length of the value of the String.
return
a string representing the sequence of characters contained in the subarray of the character array argument.
exception
IndexOutOfBoundsException if offset is negative, or count is negative, or offset+count is larger than data.length.

	return new String(data, offset, count);
    
public static java.lang.StringvalueOf(boolean b)
Returns the string representation of the boolean argument.

param
b a boolean.
return
if the argument is true, a string equal to "true" is returned; otherwise, a string equal to "false" is returned.

	return b ? "true" : "false";
    
public static java.lang.StringvalueOf(char c)
Returns the string representation of the char argument.

param
c a char.
return
a string of length 1 containing as its single character the argument c.

	char data[] = {c};
	return new String(0, 1, data);
    
public static java.lang.StringvalueOf(int i)
Returns the string representation of the int argument.

The representation is exactly the one returned by the Integer.toString method of one argument.

param
i an int.
return
a string representation of the int argument.
see
java.lang.Integer#toString(int, int)

        return Integer.toString(i, 10);
    
public static java.lang.StringvalueOf(long l)
Returns the string representation of the long argument.

The representation is exactly the one returned by the Long.toString method of one argument.

param
l a long.
return
a string representation of the long argument.
see
java.lang.Long#toString(long)

        return Long.toString(l, 10);
    
public static java.lang.StringvalueOf(float f)
Returns the string representation of the float argument.

The representation is exactly the one returned by the Float.toString method of one argument.

param
f a float.
return
a string representation of the float argument.
see
java.lang.Float#toString(float)

	return Float.toString(f);
    
public static java.lang.StringvalueOf(double d)
Returns the string representation of the double argument.

The representation is exactly the one returned by the Double.toString method of one argument.

param
d a double.
return
a string representation of the double argument.
see
java.lang.Double#toString(double)

	return Double.toString(d);