CODEWITHSUNDEEP
java
gameover
gameover

Reputation: 12013

Default values of instance variables and local variables

I read that Java provides default values to class properties, but not to local variables. Is that correct?

If so, what is the reason behind this? When you are doing something good, why not do it all the way?

Upvotes: 15

Views: 8166

Answers (2)

Matthias
Matthias

Reputation: 12259

The non-technical reason behind may also be the following one:

If you declare a local variable, you do this in order to use it. And usage is connected with assigning a value. Therefore, accessing a declared, but not initialized, variable does not make that much sense - the programmer might simply have forgotten to initialize the variable.

Fields, however, might only be used until or after a specified point in the object's lifetime. Forcing the programmer to initialize them all would not be good.

Upvotes: 1

Michael Krauklis
Michael Krauklis

Reputation: 3954

Standard local variables are stored on the stack and aren't actually created until they are initialized. If a local variable isn't used, it doesn't go on the stack. Member variables, however, are allocated in the heap, and thusly have a default placeholder (null reference or default primitive).

Upvotes: 27

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