1. 源码

  public class Object {

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

    @HotSpotIntrinsicCandidate
    public Object() {}

    @HotSpotIntrinsicCandidate
    public final native Class<?> getClass();

    @HotSpotIntrinsicCandidate
    public native int hashCode();

    public boolean equals(Object obj) {
        return (this == obj);
    }

    @HotSpotIntrinsicCandidate
    protected native Object clone() throws CloneNotSupportedException;

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

    @HotSpotIntrinsicCandidate
    public final native void notify();

    @HotSpotIntrinsicCandidate
    public final native void notifyAll();

    public final void wait() throws InterruptedException {
        wait(0L);
    }

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

    public final void wait(long timeoutMillis, int nanos) throws InterruptedException {
        if (timeoutMillis < 0) {
            throw new IllegalArgumentException("timeoutMillis value is negative");
        }

        if (nanos < 0 || nanos > 999999) {
            throw new IllegalArgumentException(
                                "nanosecond timeout value out of range");
        }

        if (nanos > 0 && timeoutMillis < Long.MAX_VALUE) {
            timeoutMillis++;
        }

        wait(timeoutMillis);
    }

  	@Deprecated(since="9")
    protected void finalize() throws Throwable { }
}

2. 涉及关键词

2.1 Native

Java中Native关键字的作用
调用其他语言的关键字。例如海康威视的SDK为C语言编译之后的DLL文件，但是提供的有JAVA 使用方案，就是采用Native (JNI)实现的。

  HCNetSDK INSTANCE = (HCNetSDK) Native.loadLibrary(dllPath + "HCNetSDK.dll", HCNetSDK.class);

通过以上方法返回一个接口的实例化对象，通过编写接口提供和dll相同的方法和参数实现调用dll文件的方法.

2.2 @HotSpotIntrinsicCandidate

网上都说Java 9引入的新特性，JDK的源码中，被@HotSpotIntrinsicCandidate标注的方法，在HotSpot中都有一套高效的实现，该高效实现基于CPU指令，运行时，HotSpot维护的高效实现会替代JDK的源码实现，从而获得更高的效率。但本人未找到具体的处理方法，在此挖个坑