"Polymorphism" means "A method(call?) acts different
depending upon the nature(type) of the parameter which
is passed"

Generally polymorphism helps robust Type checking at
the compilation time & making the programmer's life
little bit easier (atleast we dont want learn
different different method names for each type it
accepts)

If you want more info just go through
"java.lang.String" class's javadoc info. there u can c
a method named "valueOf()" for each & every
type(int,float,double,boolean,char,etc.,)

thnks to Polymorphism so we dont want to remember a
unique name for each & every type toIntValueOf,
toFloatValueOf, toDoubleValueOf,
toBooleanValueOf,toCharValueOf & (may be
toNullValueOf()!!!!!!!!)

try the following ex:-
----------------------
there is class "A" having "print" method with "String"
parameter, and then class "B" extending class "A"
having two more methods with the same name ("print")
but with diff type of parameters.

class "Poly" is extending class B (so class A as well)
calling the same method "print" with 3diff parameters,
each time the appropriate method automatically called
by the JVM & executed,,,