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.