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[Java OOP] Common Root of Java Classes

Common Root Class

java.lang.Object, link

All Java classes are derived from this common root class, that defines common behaviors.

Common behaviors include multi-threading and garbage collector etc.

Some methods


protected Object clone() throws CloneNotSupportedException

Creates and returns a copy of this object.

public boolean equals(Object obj)

Indicates whether some other object is “equal to” this one.

protected void finalize() throws Throwable

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object

public final Class getClass()

Returns the runtime class of an object.

public int hashCode()

Returns a hash code value for the object.

public String toString()

Returns a string representation of the object.

Sync-related methods

The notify, notifyAll, and wait methods of Object all play a part in synchronizing the activities of independently running threads in a program.

public final void notify()
public final void notifyAll()
public final void wait()
public final void wait(long timeout)
public final void wait(long timeout, int nanos)