Object是java所有类的父类(超类),1.0版本以来就有
这个类公有12个方法,去除重载有10个
private static native void registerNatives();
static {
registerNatives();
}
native 关键字表示调用本地方法
静态代码块在程序启动加载时就初始化
public final native Class<?> getClass();
返回运行时的类对象
public native int hashCode();
调用本地哈希方法,获得哈希值
public boolean equals(Object obj) {
return (this == obj);
}
判断对象值,如果子类重写了equals,必须重写hashCode方法
protected native Object clone() throws CloneNotSupportedException;
克隆对象,该方法是浅复制,受保护的方法,如果子类想复制,需要实现了Cloneable接口否则抛出异常
public String toString() {
return getClass().getName() + "@" + Integer.toHexString(hashCode());
}
public final native void notify();
唤醒在该对象上等待的某个线程
public final native void notifyAll();
唤醒在该对象上等待的所有线程
public final native void wait(long timeout) throws InterruptedException;
线程等待
public final void wait(long timeout, int nanos) throws InterruptedException {
if (timeout < 0) {
throw new IllegalArgumentException("timeout value is negative");
}
if (nanos < 0 || nanos > 999999) {
throw new IllegalArgumentException(
"nanosecond timeout value out of range");
}
if (nanos > 0) {
timeout++;
}
wait(timeout);
}
public final void wait() throws InterruptedException {
wait(0);
}
调用wait(long timeout)
protected void finalize() throws Throwable { }
该方法受保护,用于垃圾回收,释放资源