Class java.lang.Object 
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Class java.lang.Object 

java.lang.Object
public class Object
The root of the Class hierarchy. Every Class in the system has Object as its ultimate parent. Every variable and method defined here is available in every Object.
See Also:
Class

Constructor Index

o Object()

Method Index

o clone()
Creates a clone of the object.
o equals(Object)
Compares two Objects for equality.
o finalize()
Code to perform when this object is garbage collected.
o getClass()
Returns the Class of this Object.
o hashCode()
Returns a hashcode for this Object.
o notify()
Notifies a single waiting thread on a change in condition of another thread.
o notifyAll()
Notifies all of the threads waiting for a condition to change.
o toString()
Returns a String that represents the value of this Object.
o wait()
Causes a thread to wait forever until it is notified.
o wait(long)
Causes a thread to wait until it is notified or the specified timeout expires.
o wait(long, int)
More accurate wait.

Constructors

o Object 
  public Object()

Methods

o getClass 
  public final Class getClass()
Returns the Class of this Object. Java has a runtime representation for classes- a descriptor of type Class- which the method getClass() returns for any Object.
o hashCode 
  public int hashCode()
Returns a hashcode for this Object. Each Object in the Java system has a hashcode. The hashcode is a number that is usually different for different Objects. It is used when storing Objects in hashtables. Note: hashcodes can be negative as well as positive.
See Also:
Hashtable
o equals 
  public boolean equals(Object obj)
Compares two Objects for equality. Returns a boolean that indicates whether this Object is equivalent to the specified Object. This method is used when an Object is stored in a hashtable.
Parameters:
obj - the Object to compare with
Returns:
true if these Objects are equal; false otherwise.
See Also:
Hashtable
o clone 
  protected Object clone() throws CloneNotSupportedException
Creates a clone of the object. A new instance is allocated and a bitwise clone of the current object is place in the new object.
Returns:
a clone of this Object.
Throws: OutOfMemoryError
If there is not enough memory.
Throws: CloneNotSupportedException
Object explicitly does not want to be cloned, or it does not support the Cloneable interface.
o toString 
  public String toString()
Returns a String that represents the value of this Object. It is recommended that all subclasses override this method.
o notify 
  public final void notify()
Notifies a single waiting thread on a change in condition of another thread. The thread effecting the change notifies the waiting thread using notify(). Threads that want to wait for a condition to change before proceeding can call wait().

The method notify() can only be called by the thread that is the owner of the current object's monitor.

Throws: IllegalMonitorStateException
If the current thread is not the owner of the Object's monitor.
See Also:
wait, notifyAll
o notifyAll 
  public final void notifyAll()
Notifies all of the threads waiting for a condition to change. Threads that are waiting are generally waiting for another thread to change some condition. Thus, the thread effecting a change that more than one thread is waiting for notifies all the waiting threads using the method notifyAll(). Threads that want to wait for a condition to change before proceeding can call wait().

The method notifyAll() can only be called by the thread that is the owner of the current object's monitor.

Throws: IllegalMonitorStateException
If the current thread is not the owner of the Object's monitor.
See Also:
wait, notify
o wait 
  public final void wait(long timeout) throws InterruptedException
Causes a thread to wait until it is notified or the specified timeout expires.

The method wait() can only be called from within a synchronized method.

Parameters:
timeout - the maximum time to wait in milliseconds
Throws: IllegalMonitorStateException
If the current thread is not the owner of the Object's monitor.
Throws: InterruptedException
Another thread has interrupted this thread.
o wait 
  public final void wait(long timeout,
                         int nanos) throws InterruptedException
More accurate wait. The method wait() can only be called by the thread that is the owner of the current object's monitor.
Parameters:
timeout - the maximum time to wait in milliseconds
nano - additional time, in nanoseconds range 0-999999
Throws: IllegalMonitorStateException
If the current thread is not the owner of the Object's monitor.
Throws: InterruptedException
Another thread has interrupted this thread.
o wait 
  public final void wait() throws InterruptedException
Causes a thread to wait forever until it is notified.

The method wait() can only be called from within a synchronized method

Throws: IllegalMonitorStateException
If the current thread is not the owner of the Object's monitor.
Throws: InterruptedException
Another thread has interrupted this thread.
o finalize 
  protected void finalize() throws Throwable
Code to perform when this object is garbage collected. The default is that nothing needs to be performed. Any exception thrown by a finalize method causes the finalization to halt. But otherwise, it is ignored. 
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