延迟加载和动态加载

String className = ... // 例如：java.util.List
List list = (List)Class.forName(className).newInstance();

package com.other.test;

public class Test {

public static void main(String[] args)
{
System.out.println("方法调用前！");
Test2.doSomething();
System.out.println("方法调用后！");
}
}

class Test2
{
static//静态块在类被加载时候运行
{
System.out.println("I am now loaded");
}

public static void doSomething() {}
}