Java에서 객체의 크기를 결정하는 방법은 무엇입니까?

<code class="java">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);
    }
}</code>

<code class="xml"><instrumentation>
  <main class="ObjectSizeFetcher">
    <option name="tools" value="all"/>
  </main>
</instrumentation></code>

<code class="java">public class C {
    private int x;
    private int y;

    public static void main(String[] args) {
        System.out.println(ObjectSizeFetcher.getObjectSize(new C()));
    }
}</code>