Java源码学习-Object

Source Code学习之Java万类之祖：Object

Methods:

方法不多，一个一个来看。

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 {
  //装载本地库函数。基本上属于 Native 方法的多少都跟 JVM带点关系，这些追踪的到最后都会变成.cpp，所以就不深究了。
    private static native void registerNatives();
  
  //装载本地库函数，用于载入Obejct类中调用的本地库
    static {
        registerNatives();
    }

  //返回对象的运行时类型 由 JVM 实现 为反射提供了基础
    public final native Class<?> getClass();

  //重点关注方法，与 equals() 方法互相对应。
    public native int hashCode();

  //比较对象地址值是否相等
    public boolean equals(Object obj) {
        return (this == obj);
    }

   protected native Object clone() throws CloneNotSupportedException;
  //返回对象的全类名(包含包名),Integer.toHexString(hashCode()) 是以16进制无符号整数形式返回此哈希吗的字符串表示形式。
   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 { }