memory - In Java, what is the best way to determine the size of an object? - Stack Overflow

memory - In Java, what is the best way to determine the size of an object? - Stack Overflow

You can use the java.lang.instrument package

Compile and put this class in a JAR:

import java.lang.instrument.Instrumentation;    public class ObjectSizeFetcher {      private static Instrumentation instrumentation;        public static void premain(String args, Instrumentation inst) {          instrumentation = inst;      }        public static long getObjectSize(Object o) {          return instrumentation.getObjectSize(o);      }  }

Add the following to your MANIFEST.MF:

Premain-Class: ObjectSizeFetcher

Use getObjectSize:

public class C {      private int x;      private int y;        public static void main(String [] args) {          System.out.println(ObjectSizeFetcher.getObjectSize(new C()));      }  }

Invoke with:

java -javaagent:ObjectSizeFetcherAgent.jar C

Read full article from memory - In Java, what is the best way to determine the size of an object? - Stack Overflow