attach to JVM use java attach API

java-attach-api.java

import com.sun.tools.attach.VirtualMachine;
import com.sun.tools.attach.VirtualMachineDescriptor;
import java.util.List;

public class ListVM{
  public static void main(String[] args){
        List<VirtualMachineDescriptor> vmList = VirtualMachine.list();
        for(VirtualMachineDescriptor vm : vmList){
		System.out.println("name: " + vm.displayName() + " id :" + vm.id());
		try{
			VirtualMachine vm0 = VirtualMachine.attach(vm.id());
			// load agent, agnet class's agentmain will be invoked. 
			vm0.loadAgent("/root/tmp/ChinaAgent.jar");
			System.out.println("Load agent done.");
			vm0.detach();
		}catch(Exception e) {
			System.out.println("exception : " + e.getMessage());
		}
        }
  }
}

compile :

javac -cp /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51.x86_64/lib/tools.jar ListVM.java 

run :

 java -cp /usr/lib/jvm/java-1.7.0-openjdk-1.7.0.51.x86_64/lib/tools.jar ListVM

tools.jar class path needed