Can Java's JConsole be used to automatically configure memory?

Question

I am studying about Java JMX and JConsole. I am curious about the memory management abilities of JConsole. For example, there is a "Perform GC" button in the Memory tab :

Suppose I have simple Java app that eats up memory, something like this :

public class MemoryEater
{
  public static void main(String[] args)
  {
    Vector v = new Vector();
    while (true)
    {
      byte b[] = new byte[1048576];
      v.add(b);
      Runtime rt = Runtime.getRuntime();
      System.out.println( "free memory: " + rt.freeMemory() );
    }
  }
}

Would there be a way to configure JConsole to prevent this app from consuming X amount of memory? Or do I need to make a new MBean via JMX ? thanks

Answer 1

Would there be a way to configure JConsole to prevent this app from consuming X amount of memory?

From JConsole we cannot tune/control the memory limits. Only option I see is using -Xmx during startup of java process. Looking at the below screenshot, JConsole exposes memory parameters as only as readable but not writable.

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Or do I need to make a new MBean via JMX ?

Even if we write our own MBean I don't think it is possible to change the memory limits of java process at runtime. The only way is to configure the memory limits during the start up using -Xms and -Xmx.

Unless the question is specific to your example code, where in you want to limit the number of elements that can be added to the Vector through JMX Bean and there by limiting the memory consumption, which is do-able, but I doubt if that is what you are looking for.