package com.test;

import java.lang.management.ManagementFactory;
import java.lang.management.RuntimeMXBean;

public class Target {

  public static void main(String[] args) throws InterruptedException {
    System.out.println(getProcessID());
    while(true) {
      Thread.sleep(10000);
    }
  }

  public static final int getProcessID() { 
    RuntimeMXBean runtimeMXBean = ManagementFactory.getRuntimeMXBean();
    System.out.println(runtimeMXBean.getName());
    return Integer.valueOf(runtimeMXBean.getName().split("@")[0]) 
        .intValue(); 
  } 

}

2896@PC-20150603VRPL
2896

package com.test;

import java.util.HashSet;
import java.util.Set;

import sun.jvmstat.monitor.MonitoredHost;
import sun.jvmstat.monitor.MonitoredVm;
import sun.jvmstat.monitor.MonitoredVmUtil;
import sun.jvmstat.monitor.VmIdentifier;

public class ProcessID {

  public static void main(String[] args) throws Exception {
     // 获取监控主机
     MonitoredHost local = MonitoredHost.getMonitoredHost("localhost");
     // 取得所有在活动的虚拟机集合
     Set<?> vmlist = new HashSet<Object>(local.activeVms());
     // 遍历集合，输出PID和进程名
     for(Object process : vmlist) {
       MonitoredVm vm = local.getMonitoredVm(new VmIdentifier("//" + process));
       // 获取类名
       String processname = MonitoredVmUtil.mainClass(vm, true);
       System.out.println(process + " ------> " + processname);
     }
   }
}

2752 ------> 
5172 ------> com.test.Target
5308 ------> com.test.ProcessID

package com.test;

import java.net.URISyntaxException;
import java.util.HashSet;
import java.util.Set;

import sun.jvmstat.monitor.MonitorException;
import sun.jvmstat.monitor.MonitoredHost;
import sun.jvmstat.monitor.MonitoredVm;
import sun.jvmstat.monitor.MonitoredVmUtil;
import sun.jvmstat.monitor.VmIdentifier;

public class ProcessID {

  public static void main(String[] args) throws Exception {
     int pid = getProcess(Target.class);
     System.out.println("PID: "+pid);
  }

  public static int getProcess(Class<?> cls) throws MonitorException, URISyntaxException {
    if(cls == null) {
      return -1;
    }

    // 获取监控主机
    MonitoredHost local = MonitoredHost.getMonitoredHost("localhost");
    // 取得所有在活动的虚拟机集合
    Set<?> vmlist = new HashSet<Object>(local.activeVms());
    // 遍历集合，输出PID和进程名
    for(Object process : vmlist) {
      MonitoredVm vm = local.getMonitoredVm(new VmIdentifier("//" + process));
      // 获取类名
      String processname = MonitoredVmUtil.mainClass(vm, true);
      if(cls.getName().equals(processname)) {
        return ((Integer)process).intValue();
      }
    }
    return -1;
  }
}