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Calculate JVM CPU Usage Using MXBeans
/* JVMCPUUsage
*
* Calculate JVM CPU usage on older than JDK version 7 using MXBeans.
*
* First initiate MBeanServerConnection using `openMBeanServerConnection` method. Then
* create proxy connections to MXBeans using `getMXBeanProxyConnections` and after that
* poll `getJvmCpuUsage` method periodically.
*
* JVMCPUUsage is a free Java class:
* you can redistribute it and/or modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, either version 3 of the License, or(at your option)
* any later version. This code is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
* See COPYING for a copy of the GNU General Public License. If not, see <http://www.gnu.org/licenses/>.
*
* Copyright (C) 2017 Lahiru Pathirage <lpsandaruwan@gmail.com> on 3/27/17.
*/
import javax.management.MBeanServerConnection;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
import java.io.IOException;
import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import java.lang.management.RuntimeMXBean;
public class JVMCPUUsage {
// hardcoded connection parameters
private final String HOSTNAME = "localhost";
private final int PORT = 9999;
private MBeanServerConnection mBeanServerConnection;
private com.sun.management.OperatingSystemMXBean peOperatingSystemMXBean;
private OperatingSystemMXBean operatingSystemMXBean;
private RuntimeMXBean runtimeMXBean;
// keeping previous timestamps
private long previousJvmProcessCpuTime = 0;
private long previousJvmUptime = 0;
// initiate and prepare MBeanServerConnection
public void openMBeanServerConnection() throws IOException {
// initiate address of the JMX API connector server
String serviceURL = "service:jmx:rmi:///jndi/rmi://" + HOSTNAME + ":" + PORT + "/jmxrmi";
JMXServiceURL jmxServiceURL = new JMXServiceURL(serviceURL);
// initiate client side JMX API connector
// here we set environment attributes to null, because it is not a necessity to what we're going to do
JMXConnector jmxConnector = JMXConnectorFactory.connect(jmxServiceURL, null);
// initiate management bean server connection
mBeanServerConnection = jmxConnector.getMBeanServerConnection();
}
// initiate and prepare MXBean interfaces proxy connections
public void getMXBeanProxyConnections() throws IOException {
peOperatingSystemMXBean = ManagementFactory.newPlatformMXBeanProxy(
mBeanServerConnection,
ManagementFactory.OPERATING_SYSTEM_MXBEAN_NAME,
com.sun.management.OperatingSystemMXBean.class
);
operatingSystemMXBean = ManagementFactory.newPlatformMXBeanProxy(
mBeanServerConnection,
ManagementFactory.OPERATING_SYSTEM_MXBEAN_NAME,
OperatingSystemMXBean.class
);
runtimeMXBean = ManagementFactory.newPlatformMXBeanProxy(
mBeanServerConnection,
ManagementFactory.RUNTIME_MXBEAN_NAME,
RuntimeMXBean.class
);
}
// Get JVM CPU usage
public float getJvmCpuUsage() {
// elapsed process time is in nanoseconds
long elapsedProcessCpuTime = peOperatingSystemMXBean.getProcessCpuTime() - previousJvmProcessCpuTime;
// elapsed uptime is in milliseconds
long elapsedJvmUptime = runtimeMXBean.getUptime() - previousJvmUptime;
// total jvm uptime on all the available processors
long totalElapsedJvmUptime = elapsedJvmUptime * operatingSystemMXBean.getAvailableProcessors();
// calculate cpu usage as a percentage value
// to convert nanoseconds to milliseconds divide it by 1000000 and to get a percentage multiply it by 100
float cpuUsage = elapsedProcessCpuTime / (totalElapsedJvmUptime * 10000F);
// set old timestamp values
previousJvmProcessCpuTime = peOperatingSystemMXBean.getProcessCpuTime();
previousJvmUptime = runtimeMXBean.getUptime();
return cpuUsage;
}
}
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