"throw" is used to handle user-defined exception.
JVM handles the exceptions which are specified by "throws"

throws is used to throw an exception from the  method 
without handling  that exception where as 'throw' is used 
to throw the exception to catch block and handle it.

throw is used for to through exception system explicitly,and
throws is u sed for to throws exception means throws
ioexception and servletexception and etc.........

hi pavitra u r nswer is wrong

throw will throws the exception,
and throws declares that the function will throw an exception
you should catch all every functions throwing and exception
u declare it or catch it

throws keyword is used 2 delegate the responsibility of 
exception handling 2 caller method where as throw keyword 
used 2 hand over the creted customised excetion object 2 
jvm 2 handle the excepion.

throws --> throws declare that it throws the exception to 
the calling method.

throw -->  it is surrounded by the try catch block actually 
it does the work, of throwing the exception.

For Example:

public void testMethod() throws BusinessException
{ 
  try
    {
    }
   catch(Exception exe)
   {
     // catch all the exceptions and provide some meaningful
        message
      throw BusinessException("An error occured while     
trying to connect to DB");
   }   
         
}

throws:
Method capable of raising an exception but not handling the 
same. i.e to say no Try Catch block is implemented in the 
Method, to handle the exception.
The callers should create the Try Catch Block to safeguard 
against the exception.
If the above is not followed it would result in Compilation 
errors.

throw:
The method that raises the exception also handles the same 
in its Catch block.
If unhandled the exception can also be handles by the 
Callers Try Catch Block.
Hope this makes sense.

throw- means user defined exception. we want throw manually
throw the exception.
throws- means jvm going to take all exception.

In Throws, what ever the exception you are declaring are 
handle by JVM. If it is a user defined exception in throws 
block, JVM doesn't know when to throw that exception. For 
this purpose we use Throw for a certain conditions/logic to 
throw these user defined exceptions.

I think the above makes sense.

throws specifies that a method could throw an exception 
while throw is used to throw a particular type of exception

throw  IOException;

public void clem()throws exception

throw : throw is used to throw user defined exceptions.
        For ex: MyException written by user.it may be either
        checked or unchecked exception.

throws: throws is used to throw exception those are handled by
         JVM directly.
         throws is used in method declaration to 
         intimate user that, it throw the exception that must 
         be handled by calling method.

Note :use throws when your method does not handle exception.

throw : throw is used to throw exception by user whenever he
        feels to throw exceptions. throw is used to throw 
         either user defined or runtime exception.
         for ex : throw new MyException(), here MyException 
                  is user written exception.
                  throw new NullPointerException(), here 
                  NullPointerException is RuntimeException.

throws: throws is used by the method to throw exception to
        the calling method. And method itself does not able
        to handle it so it throws to calling method.

throw - It is used to throw an Exception.
throws - This is used to specifies that the method can 
throw Exception

throws is used for throwing an exception from a method to 
jvm, the jvm should handle it.where us throw is used when 
user needs to raise his own exception.

throw: It is used to explicitly or manually throw an 
exception.it can throw user defined exceptions.

throws:It tells that exception to b handled by calling 
function. It tells caller that what exception that method 
could throw.