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/*
* @test
* @bug 4530538
* @summary Basic Test for HotspotThreadMBean.getInternalThreadCount()
* and getInternalThreadCpuTime()
* @author Mandy Chung
*/
import sun.management.*;
import java.util.*;
import java.lang.management.ThreadMXBean;
import java.lang.management.ManagementFactory;
public class GetInternalThreads {
private static HotspotThreadMBean mbean =
ManagementFactoryHelper.getHotspotThreadMBean();
// Minimum number of VM internal threads
// VM thread, watcher thread, Low memory detector, compiler thread
private static final long MIN_VALUE_FOR_PASS = 4;
private static final long MAX_VALUE_FOR_PASS = Long.MAX_VALUE;
public static void main(String[] args) {
long value = mbean.getInternalThreadCount();
if (value < MIN_VALUE_FOR_PASS || value > MAX_VALUE_FOR_PASS) {
throw new RuntimeException("Internal thread count " +
"illegal value: " + value + " " +
"(MIN = " + MIN_VALUE_FOR_PASS + "; " +
"MAX = " + MAX_VALUE_FOR_PASS + ")");
}
System.out.println("Internal Thread Count = " + value);
ThreadMXBean thread =
ManagementFactory.getThreadMXBean();
if (!thread.isThreadCpuTimeSupported()) {
System.out.println("Thread Cpu Time is not supported.");
return;
}
Map times = mbean.getInternalThreadCpuTimes();
Iterator iter = times.entrySet().iterator();
for (; iter.hasNext(); ) {
Map.Entry entry = (Map.Entry) iter.next();
System.out.println(entry.getKey() +
" CPU time = " + entry.getValue() + "ns");
if (((Long) entry.getValue()).longValue() < 0) {
throw new RuntimeException("Thread CPU time" +
"illegal value: " + entry.getValue());
}
}
System.out.println("Test passed.");
}
}