CPU and memory usage statistics in Java application

[Arkie]

For those that want to know how to see the CPU and memory usage statistics in a Java application here's a demo that P. Lawrey wrote 

Code

GeSHi (java):
import java.lang.management.ManagementFactory;
import java.lang.management.OperatingSystemMXBean;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.List;
 
public class OSBeanTester {
    public static void main(String... args) {
        printUsage();
        System.out.println("Calendars are surprisingly expensive. Creating 100000 Calendars");
        List<Calendar> calendars = new ArrayList<Calendar>();
        for (int i = 0; i < 100000; i++)
            calendars.add(new GregorianCalendar());
        printUsage();
    }
 
    private static void printUsage() {
        OperatingSystemMXBean operatingSystemMXBean = ManagementFactory.getOperatingSystemMXBean();
        for (Method method : operatingSystemMXBean.getClass().getDeclaredMethods()) {
            method.setAccessible(true);
            if (method.getName().startsWith("get") && Modifier.isPublic(method.getModifiers())) {
                Object value;
                try {
                    value = method.invoke(operatingSystemMXBean);
                } catch (Exception e) {
                    value = e;
                }
                System.out.println(method.getName() + " = " + value);
            }
        }
    }
}
 
Created by GeSHI 1.0.7.20

Output
getCommittedVirtualMemorySize = 28811264
getFreePhysicalMemorySize = 1207009280
getFreeSwapSpaceSize = 3365294080
getProcessCpuTime = 109375000
getTotalPhysicalMemorySize = 2145497088
getTotalSwapSpaceSize = 4129447936
Calendars are surprisingly expensive. Creating 100000 Calendars
getCommittedVirtualMemorySize = 91783168
getFreePhysicalMemorySize = 1154912256
getFreeSwapSpaceSize = 3302273024
getProcessCpuTime = 671875000
getTotalPhysicalMemorySize = 2145497088
getTotalSwapSpaceSize = 4129447936