sizeof java object

Question

How can we find out the size of a java object??

Example:

class Person{
    String name;  
    int age;  

    public Person(String n, int a){  
          


        

Answer 1

I think you can get something that might help you if you do something like this:

    /* First trigger classloading */
    MyObject delegate = new MyObject();

    Runtime.getRuntime().gc();

    long before = Runtime.getRuntime().freeMemory();
    MyObject delegate2 = new MyObject();
    long after = Runtime.getRuntime().freeMemory();

    System.out.println("Memory used:"+(before-after));

This will hopefully give you the answer you want, or at least an approximation.