Detailed explanation of methods and functions in Object class

I. Introduction

The Java Object class is the parent class of all classes, that is, all classes in Java inherit Object, and subclasses can use all methods of Object. The Object class is located in the java.lang package and is automatically imported at compile time. When we create a class, if we do not explicitly inherit a parent class, it will automatically inherit Object and become a subclass of Object.

2. Detailed explanation of Object method

By reading the source code, we can see that Object contains: Object(), getClass(), hashCode(), equals(), clone(), toString(), notify(), notifyAll(), wait(long), wait(long,int ), wait(), finalize() a total of twelve methods.

A brief description of the functions of these methods:

1. Object(): Default Constructor

 public Object() {
        throw new RuntimeException("Stub!");
    }
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2. clone(): Create and return a copy of this object

   @RecentlyNonNull
    protected Object clone() throws CloneNotSupportedException {
        throw new RuntimeException("Stub!");
    }
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3. equals(): Indicates whether some other object is equal to this object

 public boolean equals(@Nullable Object obj) {
        throw new RuntimeException("Stub!");
    }
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4. finalize(): This method is called by the garbage collector of an object when the garbage collector determines that there are no more references to the object

    protected void finalize() throws Throwable {
        throw new RuntimeException("Stub!");
    }
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5. getClass(): Returns the runtime class of an object

    @NonNull
    public final Class<?> getClass() {
        throw new RuntimeException("Stub!");
    }
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6. hashCode(): Returns the hash value of the object

    public int hashCode() {
        throw new RuntimeException("Stub!");
    }
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7. notify(): wake up a single thread waiting on this object monitor

    public final native void notify();
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8. notifyAll(): wake up all threads waiting on this object monitor

    public final native void notifyAll();
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9. toString(): Returns the string representation of the object

    @NonNull
    public String toString() {
        throw new RuntimeException("Stub!");
    }
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10. wait(): Causes the current thread to wait until other threads call notify() or notifyAll() of this object

    public final void wait() throws InterruptedException {
        throw new RuntimeException("Stub!");
    }
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11. wait(long timeout): Causes the current thread to wait to call notify() or notifyAll() of this object

    public final void wait(long timeout) throws InterruptedException {
        throw new RuntimeException("Stub!");
    }
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12. wait(long timeout, int nanos): Causes the current thread to wait until another thread calls notify() or notifyAll() of this object, or some other thread interrupts the current thread, or some actual amount of time has passed

    public final native void wait(long var1, int var3) throws InterruptedException;
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