How to Attach to a Running Java Process

When running Java programs, it is advantageous to monitor those programs and their execution externally. You may want to attach a monitoring tool to the program's process to record the state of the program. By using the "attach" API provided in the Java Development Kit (JDK), you can attach a monitoring agent to a running Virtual Machine instance, which represents a running program, and monitor the activity.

Things You'll Need

• Java Development Kit

Instructions

1. Create a Virtual Machine object to attach to the process through its unique ID:

   import java.lang.management.\*;
   import java.io.\*;
   import java.util.\*;
   import javax.management.\*;
   import javax.management.remote.\*;
   import com.sun.tools.attach.\*;

   public class testing{

   public static void main(String[] args){

   VirtualMachine vm = VirtualMachine.attach(processid);
   }
   }

2. Select an agent program (usually a jar):

   VirtualMachine vm = VirtualMachine.attach(processid);
   String agent = "C:\...agent_name.jar"; // variable depending on agent program

3. Attach the agent to the Virtual Machine process to monitor:

   VirtualMachine vm = VirtualMachine.attach(processid);
   String agent = "C:\...agent_name.jar";
   vm.loadAgent(agent);

References

• Oracle: The Attach API