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You can use the java.lang.instrumentation package:

docs.oracle.com/javase/7/docs/api/java/lang/instrument/Instrumentation.html

It has a method that can be used to get the implementation specific approximation of object size, as well as overhead associated with the object.

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);
}
}

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

this code,i already tried,but not working....

yes, I also faced the same problem

you can try this.

stackoverflow.com/questions/9368764/calculate-size-of-object-in-java

The boolean mapping was done with a 32bit CPU in mind. The int value has 32 bits so it can be processed in one operation.

Here's a solution from Peter Norvig's Java IAQ: Infrequently Answered Questions (norvig.com/java-iaq.html#sizeof) to measure the size (with some imprecision):

static Runtime runtime = Runtime.getRuntime();
...
long start, end;
Object obj;
runtime.gc();
start = runtime.freememory();
obj = new Object(); // Or whatever you want to look at
end =  runtime.freememory();
System.out.println("That took " + (start-end) + " bytes.");

Its simple. We will have to measure it.

we should serialize the object and get the bytes required to store it.

Sorry, Now I got the question.

We should search for its size on Google search.

Sorry, Now I got the question.

We should search for its size on Google search.