小知识

1

image.png

2

Object类源码，回顾一下！

package java.lang;

/**
 * Class {@code Object} is the root of the class hierarchy.
 * Every class has {@code Object} as a superclass. All objects,
 * including arrays, implement the methods of this class.
 *
 * @author  unascribed
 * @see     java.lang.Class
 * @since   JDK1.0
 */
public class Object {

    private static native void registerNatives();
    static {
        registerNatives();
    }

    public final native Class getClass();

    public native int hashCode();

    public boolean equals(Object obj) {
        return (this == obj);
    }
    protected native Object clone() throws CloneNotSupportedException;

    public String toString() {
        return getClass().getName() + "@" + Integer.toHexString(hashCode());
    }
    public final native void notify();

    public final native void notifyAll();

    public final native void wait(long timeout) throws InterruptedException;

  
    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);
    }
    protected void finalize() throws Throwable { }
}