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JavaEnvUtils.javaAPI DocApache Ant 1.7016211Wed Dec 13 06:16:20 GMT 2006org.apache.tools.ant.util

JavaEnvUtils

public final class JavaEnvUtils extends Object
A set of helper methods related to locating executables or checking conditons of a given Java installation.
since
Ant 1.5

Fields Summary
private static final boolean
IS_DOS
Are we on a DOS-based system
private static final boolean
IS_NETWARE
Are we on Novell NetWare
private static final boolean
IS_AIX
Are we on AIX
private static final String
JAVA_HOME
shortcut for System.getProperty("java.home")
private static final FileUtils
FILE_UTILS
FileUtils instance for path normalization
private static String
javaVersion
Version of currently running VM.
private static int
javaVersionNumber
floating version of the JVM
public static final String
JAVA_1_0
Version constant for Java 1.0
public static final String
JAVA_1_1
Version constant for Java 1.1
public static final String
JAVA_1_2
Version constant for Java 1.2
public static final String
JAVA_1_3
Version constant for Java 1.3
public static final String
JAVA_1_4
Version constant for Java 1.4
public static final String
JAVA_1_5
Version constant for Java 1.5
public static final String
JAVA_1_6
Version constant for Java 1.6
private static boolean
kaffeDetected
Whether this is the Kaffe VM
private static Vector
jrePackages
array of packages in the runtime
Constructors Summary
private JavaEnvUtils()
Methods Summary
private static java.lang.StringaddExtension(java.lang.String command)
Adds a system specific extension to the name of an executable.

since
Ant 1.5

        // This is the most common extension case - exe for windows and OS/2,
        // nothing for *nix.
        return command + (IS_DOS ? ".exe" : "");
private static voidbuildJrePackages()
demand creation of the package list. When you add a new package, add a new test below.

        jrePackages = new Vector();
        switch(javaVersionNumber) {
            case 16:
            case 15:
                //In Java1.5, the apache stuff moved.
                jrePackages.addElement("com.sun.org.apache");
                //fall through.
            case 14:
                if (javaVersionNumber == 14) {
                    jrePackages.addElement("org.apache.crimson");
                    jrePackages.addElement("org.apache.xalan");
                    jrePackages.addElement("org.apache.xml");
                    jrePackages.addElement("org.apache.xpath");
                }
                jrePackages.addElement("org.ietf.jgss");
                jrePackages.addElement("org.w3c.dom");
                jrePackages.addElement("org.xml.sax");
                // fall through
            case 13:
                jrePackages.addElement("org.omg");
                jrePackages.addElement("com.sun.corba");
                jrePackages.addElement("com.sun.jndi");
                jrePackages.addElement("com.sun.media");
                jrePackages.addElement("com.sun.naming");
                jrePackages.addElement("com.sun.org.omg");
                jrePackages.addElement("com.sun.rmi");
                jrePackages.addElement("sunw.io");
                jrePackages.addElement("sunw.util");
                // fall through
            case 12:
                jrePackages.addElement("com.sun.java");
                jrePackages.addElement("com.sun.image");
                // are there any here that we forgot?
                // fall through
            case 11:
            default:
                //things like sun.reflection, sun.misc, sun.net
                jrePackages.addElement("sun");
                jrePackages.addElement("java");
                jrePackages.addElement("javax");
                break;
        }
public static java.io.FilecreateVmsJavaOptionFile(java.lang.String[] cmd)
Writes the command into a temporary DCL script and returns the corresponding File object. It is the job of the caller to delete the file on exit.

param
cmd the command.
return
the file containing the command.
throws
IOException if there is an error writing to the file.

        File script = FILE_UTILS.createTempFile("ANT", ".JAVA_OPTS", null);
        PrintWriter out = null;
        try {
            out = new PrintWriter(new BufferedWriter(new FileWriter(script)));
            for (int i = 0; i < cmd.length; i++) {
                out.println(cmd[i]);
            }
        } finally {
            FileUtils.close(out);
        }
        return script;
private static java.io.FilefindInDir(java.lang.String dirName, java.lang.String commandName)
Look for an executable in a given directory.

return
null if the executable cannot be found.

        File dir = FILE_UTILS.normalize(dirName);
        File executable = null;
        if (dir.exists()) {
            executable = new File(dir, addExtension(commandName));
            if (!executable.exists()) {
                executable = null;
            }
        }
        return executable;
public static java.lang.StringgetJavaHome()
Return the value of ${java.home}

return
the java home value.

        return JAVA_HOME;
public static java.lang.StringgetJavaVersion()
Returns the version of Java this class is running under.

return
the version of Java as a String, e.g. "1.1"



     

        // Determine the Java version by looking at available classes
        // java.net.Proxy was introduced in JDK 1.5
        // java.lang.CharSequence was introduced in JDK 1.4
        // java.lang.StrictMath was introduced in JDK 1.3
        // java.lang.ThreadLocal was introduced in JDK 1.2
        // java.lang.Void was introduced in JDK 1.1
        // Count up version until a NoClassDefFoundError ends the try

        try {
            javaVersion = JAVA_1_0;
            javaVersionNumber = 10;
            Class.forName("java.lang.Void");
            javaVersion = JAVA_1_1;
            javaVersionNumber++;
            Class.forName("java.lang.ThreadLocal");
            javaVersion = JAVA_1_2;
            javaVersionNumber++;
            Class.forName("java.lang.StrictMath");
            javaVersion = JAVA_1_3;
            javaVersionNumber++;
            Class.forName("java.lang.CharSequence");
            javaVersion = JAVA_1_4;
            javaVersionNumber++;
            Class.forName("java.net.Proxy");
            javaVersion = JAVA_1_5;
            javaVersionNumber++;
            Class.forName("java.util.ServiceLoader");
            javaVersion = JAVA_1_6;
            javaVersionNumber++;
        } catch (Throwable t) {
            // swallow as we've hit the max class version that
            // we have
        }
        kaffeDetected = false;
        try {
            Class.forName("kaffe.util.NotImplemented");
            kaffeDetected = true;
        } catch (Throwable t) {
            // swallow as this simply doesn't seem to be Kaffe
        }
    
        return javaVersion;
public static intgetJavaVersionNumber()
Returns the version of Java this class is running under. This number can be used for comparisions; it will always be

return
the version of Java as a number 10x the major/minor, e.g Java1.5 has a value of 15

        return javaVersionNumber;
public static java.lang.StringgetJdkExecutable(java.lang.String command)
Finds an executable that is part of a JDK installation based on the java.home system property.

You typically find them in JAVA_HOME/bin if JAVA_HOME points to your JDK installation.

param
command the java executable to find.
return
the path to the command.
since
Ant 1.5

        if (IS_NETWARE) {
            // Extrapolating from:
            // "NetWare may have a "java" in that directory, but 99% of
            // the time, you don't want to execute it" -- Jeff Tulley
            // <JTULLEY@novell.com>
            return command;
        }

        File jExecutable = null;

        if (IS_AIX) {
            // On IBM's JDK 1.2 the directory layout is different, 1.3 follows
            // Sun's layout.
            jExecutable = findInDir(JAVA_HOME + "/../sh", command);
        }

        if (jExecutable == null) {
            jExecutable = findInDir(JAVA_HOME + "/../bin", command);
        }

        if (jExecutable != null) {
            return jExecutable.getAbsolutePath();
        } else {
            // fall back to JRE bin directory, also catches JDK 1.0 and 1.1
            // where java.home points to the root of the JDK and Mac OS X where
            // the whole directory layout is different from Sun's
            return getJreExecutable(command);
        }
public static java.lang.StringgetJreExecutable(java.lang.String command)
Finds an executable that is part of a JRE installation based on the java.home system property.

java, keytool, policytool, orbd, rmid, rmiregistry, servertool and tnameserv are JRE executables on Sun based JRE's.

You typically find them in JAVA_HOME/jre/bin if JAVA_HOME points to your JDK installation. JDK < 1.2 has them in the same directory as the JDK executables.

param
command the java executable to find.
return
the path to the command.
since
Ant 1.5

        if (IS_NETWARE) {
            // Extrapolating from:
            // "NetWare may have a "java" in that directory, but 99% of
            // the time, you don't want to execute it" -- Jeff Tulley
            // <JTULLEY@novell.com>
            return command;
        }

        File jExecutable = null;

        if (IS_AIX) {
            // On IBM's JDK 1.2 the directory layout is different, 1.3 follows
            // Sun's layout.
            jExecutable = findInDir(JAVA_HOME + "/sh", command);
        }

        if (jExecutable == null) {
            jExecutable = findInDir(JAVA_HOME + "/bin", command);
        }

        if (jExecutable != null) {
            return jExecutable.getAbsolutePath();
        } else {
            // Unfortunately on Windows java.home doesn't always refer
            // to the correct location, so we need to fall back to
            // assuming java is somewhere on the PATH.
            return addExtension(command);
        }
public static java.util.VectorgetJrePackageTestCases()
Testing helper method; kept here for unification of changes.

return
a list of test classes depending on the java version.

        Vector tests = new Vector();
        tests.addElement("java.lang.Object");
        switch(javaVersionNumber) {
            case 16:
            case 15:
                tests.addElement(
                    "com.sun.org.apache.xerces.internal.jaxp.datatype.DatatypeFactoryImpl ");
                // Fall tru
            case 14:
                tests.addElement("sun.audio.AudioPlayer");
                if (javaVersionNumber == 14) {
                    tests.addElement("org.apache.crimson.parser.ContentModel");
                    tests.addElement("org.apache.xalan.processor.ProcessorImport");
                    tests.addElement("org.apache.xml.utils.URI");
                    tests.addElement("org.apache.xpath.XPathFactory");
                }
                tests.addElement("org.ietf.jgss.Oid");
                tests.addElement("org.w3c.dom.Attr");
                tests.addElement("org.xml.sax.XMLReader");
                // fall through
            case 13:
                tests.addElement("org.omg.CORBA.Any");
                tests.addElement("com.sun.corba.se.internal.corba.AnyImpl");
                tests.addElement("com.sun.jndi.ldap.LdapURL");
                tests.addElement("com.sun.media.sound.Printer");
                tests.addElement("com.sun.naming.internal.VersionHelper");
                tests.addElement("com.sun.org.omg.CORBA.Initializer");
                tests.addElement("sunw.io.Serializable");
                tests.addElement("sunw.util.EventListener");
                // fall through
            case 12:
                tests.addElement("javax.accessibility.Accessible");
                tests.addElement("sun.misc.BASE64Encoder");
                tests.addElement("com.sun.image.codec.jpeg.JPEGCodec");
                // fall through
            case 11:
            default:
                //things like sun.reflection, sun.misc, sun.net
                tests.addElement("sun.reflect.SerializationConstructorAccessorImpl");
                tests.addElement("sun.net.www.http.HttpClient");
                tests.addElement("sun.audio.AudioPlayer");
                break;
        }
        return tests;
public static java.util.VectorgetJrePackages()
get a vector of strings of packages built into that platforms runtime jar(s)

return
list of packages.

        if (jrePackages == null) {
            buildJrePackages();
        }
        return jrePackages;
public static booleanisAtLeastJavaVersion(java.lang.String version)
Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class. Note that Ant now requires JDK 1.2+ so {@link #JAVA_1_0} and {@link #JAVA_1_1} need no longer be tested for.

param
version the version to check against the current version.
return
true if the version of Java is the same or higher than the given version.
since
Ant 1.7

        return javaVersion.compareTo(version) >= 0;
public static booleanisJavaVersion(java.lang.String version)
Compares the current Java version to the passed in String - assumes the argument is one of the constants defined in this class. Note that Ant now requires JDK 1.2+ so {@link #JAVA_1_0} and {@link #JAVA_1_1} need no longer be tested for.

param
version the version to check against the current version.
return
true if the version of Java is the same as the given version.
since
Ant 1.5

        return javaVersion.equals(version);
public static booleanisKaffe()
Checks whether the current Java VM is Kaffe.

return
true if the current Java VM is Kaffe.
since
Ant 1.6.3
see
http://www.kaffe.org/

        return kaffeDetected;