Object class is in the default package i.e java.lang package .
The Object class defines the basic state and behavior that all objects must have, such as the ability to compare oneself to another object, to convert to a string, to wait on a condition variable, to notify other objects that a condition variable has changed, and to return the object's class.
There are 11 methods in Object class .
It has following methods in its class
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Access ReturnType Methods
Modifier
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Public boolean * equals(Object obj)
Public int * hashCode()
Protected void * finalize()
Public Class<?> * getClass()
Protected Object * clone()
Public void * notify()
Public void * notifyAll()
Public String * toString()
Public void * wait()
Public void * wait(long timeout)
Public void * wait (long timeout , int nano )
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Now talk about its methods in general
1. equals (Object obj)
Checks whether the obj object is equal to the object on which the equals method is called .
2. hashCode()
hashCode() is used for the HashTable . It returns the hash value of the object.
3. getClass()
It returns the runtime class object .
4. clone()
It creates and returns the copy of the object .
5. notify()
It will wake up the thread waiting for the objects monitor.
6. notifyAll()
It will wakes up all the thread that are waiting for the objects monitor .
7. toString()
It will return the string representation of the object .
8. wait()
This method causes the current thread to place itself in the wait set for this object and then to
relinquish any and all synchronization claims on this object
References : Oracle Java Docs :
http://docs.oracle.com/javase/6/docs/api/java/lang/Object.html