Object Class in Java

tgugnani

7 years ago

Object Class in Java

The Object Class is one special class in Java. All the other classes are subclasses of Object class. That means Object is superclass of all other classes. Object Class defined the following methods.

Method	Purpose
`protected Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is “equal to” this one.
`protected void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`void`	`notify()` Wakes up a single thread that is waiting on this object’s monitor.
`void`	`notifyAll()` Wakes up all threads that are waiting on this object’s monitor.
`String`	`toString()` Returns a string representation of the object.
`void`	`wait()` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object.
`void`	`wait(long timeout)` Causes the current thread to wait until either another thread invokes the `notify()` method or the `notifyAll()` method for this object, or a specified amount of time has elapsed.
`void`	`wait(long timeout, int nanos)` Causes the current thread to wait until another thread invokes the `notify()` method or the `notifyAll()` method for this object, or some other thread interrupts the current thread, or a certain amount of real time has elapsed.

The methods getClass(), notify(), notifyAll(), and wait() are declared as final. You can override the others.

Inheritance in Java »

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