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small doubt

vivek gaur

Joined: Dec 30, 2005
Posts: 21
1) what does 'instanceof' operator mean?
2) what actually happens if we remove static from main?
3) when do we use Wrapper classes and why?
Christophe Verré

Joined: Nov 24, 2005
Posts: 14688

1) instanceOf will tell you the type is an object is of any particular type.
For example :

means "if myCar is a Car class or subclass then"

2) try it yourself

3) Wrapper classes offer useful methods. Have a look at the Integer class. You can convert a number into hexadecimal, octal, binary, double, float....

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Layne Lund
Ranch Hand

Joined: Dec 06, 2001
Posts: 3061
3) Wrapper classes are often used when you need an Object but you have a primitive type instead. For example, you can "wrap" an int into an Integer in order to store it in a Collection.

Java API Documentation
The Java Tutorial
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