CPU load from Java

Question

Is there a way to get the current cpu load under Java without using the JNI?

Answer 1

Under Linux you could use Runtime.exec() to execute “uptime” and evaluate the output. I don’t there’s a better way under Linux, and I don’t think there’s an equally “convenient” way under Windows.

Answer 2

On linux you could just read the file /proc/loadavg, where the first three values represent the load averages. For Windows you probably have to stick to JNI.

Answer 3

Use the ManagementFactory to get an OperatingSystemMXBean and call getSystemLoadAverage() on it.

Answer 4

This does involve JNI but there is a GPL library from Hyperic called Sigar that provides this information for all the major platforms, as well as a bunch of other OS-dependent stats like disk usage. It's worked great for us.

Answer 5

If you're using the JRockit JVM you could use JMAPI. It works for JDK 1.4, 1.5 and 1.6.

System.out.println("Total CPU-usage:" + JVMFactory.getJVM().getMachine().getCPULoad());

System.out.println("Total JVM-load :" + JVMFactory.getJVM().getJVMLoad());

for(Iterator it = JVMFactory.getJVM().getMachine().getCPUs().iterator(); it.hasNext();)
{
   CPU cpu = (CPU)it.next();
   System.out.println("CPU Description: " + cpu.getDescription());
   System.out.println("CPU Clock Frequency: " + cpu.getClockFrequency());
   System.out.println("CPU Load: " + cpu.getLoad());
   System.out.println();
}