// This agent simply registers a shutdown hook to run when the VM exits
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() {
// This code runs when the VM exits
try {
// Decide where to send our output
PrintWriter out;
if (args != null && args.length() > 0)
out = new PrintWriter(new FileWriter(args));
else
out = new PrintWriter(System.err);
// Use java.lang.management to query peak thread usage
ThreadMXBean tb = ManagementFactory.getThreadMXBean();
out.printf("Current thread count: %d%n",
tb.getThreadCount());
out.printf("Peak thread count: %d%n",
tb.getPeakThreadCount());
// Use java.lang.management to query peak memory usage
List<MemoryPoolMXBean> pools =
ManagementFactory.getMemoryPoolMXBeans();
for(MemoryPoolMXBean pool: pools) {
MemoryUsage peak = pool.getPeakUsage();
out.printf("Peak %s memory used: %,d%n",
pool.getName(), peak.getUsed());
out.printf("Peak %s memory reserved: %,d%n",
pool.getName(), peak.getCommitted());
}
// Use the Instrumentation object passed to premain()
// to get a list of all classes that have been loaded
Class[] loaded = inst.getAllLoadedClasses();
out.println("Loaded classes:");
for(Class c : loaded) out.println(c.getName());
out.close(); // close and flush the output stream
}
catch(Throwable t) {
// Exceptions in shutdown hooks are ignored so
// we've got to print this out explicitly
System.err.println("Exception in agent: " + t);
}
}
});
