java学习classCloader

public class URLtest extends ClassLoader{

    public  Class findClass(String name,byte[] b) {
      
        return defineClass(name, b, 0, b.length);
    }

public static void main(String arg[]){
   try {
   //按照类文件路径加载
URL url=new URL("file:/E:\\yunta\\Testclass\\src\\TestClass.class");
URLClassLoader classloader=new URLClassLoader(new URL[]{url});
Class<?> c = classloader.loadClass("TestClass");
Object o = c.newInstance();
Method method = c.getMethod("say");
method.invoke(o, null);
   //从io流中加载
InputStream in =  new FileInputStream(new File("E:\\yunta\\Testclass\\src\\TestClass.class"));
ByteArrayOutputStream butter = new ByteArrayOutputStream();
int i=0;
int j=0;
while(((i=in.read()))!=-1){
butter.write(i);
}
byte[] d = butter.toByteArray();
Class c1 = URLtest.class.newInstance().findClass("TestClass", d);
Object o1 = c1.newInstance();
Method method1 = c1.getMethod("say");
try {
method1.invoke(o1, null);