java代码获得类属于哪个包

import java.util.ArrayList;
import java.util.Vector;
/**
* Main.java
*
* @author outofmemory.cn
*/
public class Main {

/**
* Constructor
*/
public Main() {

findPackage(new Vector());
findPackage(new ArrayList());

findPackage("Test String");
findPackage(new Integer(1));

}

/**
* 打印对象属于哪个包
*
* @param testObject The object
*/
public void findPackage(Object testObject) {

System.out.println("Object has the package " + testObject.getClass().getPackage().getName());

}

/**
* 启动应用程序
*
* @param args the command line arguments
*/
public static void main(String[] args) {
new Main();
}
}

Object has the package java.util
Object has the package java.util
Object has the package java.lang
Object has the package java.lang