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);
}
}
加入MANIFEST.MF:
Premain-Class: ObjectSizeFetcher
然後寫個test類別
public class C {
private int x;
private int y;
public static void main(String [] args) {
System.out.println(ObjectSizeFetcher.getObjectSize(new C()));
}
}
把下面的類別編譯好放到ObjectSizeFetcherAgent.jar中
加入MANIFEST.MF:
然後寫個test類別
在命令列中這樣執行: