Object类

所有类都间接或直接的继承自Object
Object类提供了以下11个方法

protected Object clone()
boolean equals(Object obj)
protected void finalize()
Class<?> getClass()  //https://i.cnblogs.com/EditPosts.aspx?postid=10088790
int hashCode()
void notify()
void notifyAll()
String toString()
void wait()
void wait(long timeout)
void wait(long timeout, int nanos)