Why to initialize local variables explicitly

[Md. Mohd]

Dear Ranchars,
I want to know, why local variables are must to be initialized explicitly before use. We know that if we don't do that , the compiler will become red.
So what is the benefit the compiler gets if we initialize the local variables explicitly?
Also why we can not leave them as that of instance variables(which gets their default values implicitly if not assigned explicitly).

Please guide...
Thanks

[Chandrasekhar Mangipudi]

HI. Local variable are called stack/Automatic variabes. These are not instance variables and static variables that have default values.

Local variables dont have implicit default values. So we must initialize it explicitly.

[Campbell Ritchie]

I never knew compilers could change colour.

Local variables usually keep their values on a stack rather than on the heap, so there is a risk that a previous value on the stack will be read rather than a default value. The compiler therefore insists every local variable be explicitly initialised.

[Md. Mohd]

Originally posted by Campbell Ritchie:
I never knew compilers could change colour.

Local variables usually keep their values on a stack rather than on the heap, so there is a risk that a previous value on the stack will be read rather than a default value. The compiler therefore insists every local variable be explicitly initialised.

Thanks Campbell.
( Change in compiler color means the compile time error (doesn't sound good)).
Anyways,
Its true that local variables are stack/automatic variables and lives in the method stack.
It will be great if you please elaborate "a previous value on the stack will be read rather than a default value."

Thanks

[krishna pr]

Besides that, I guess the local variables are final. So a value has to be assigned to them. Correct me if I am wrong here

[fred rosenberger]

Originally posted by Campbell Ritchie:
I never knew compilers could change colour.

a place i worked put something into the build scripts where if the build failed, your normally white-on-black command window turned black-on-red.

[Anoobkumar Padmanabhan]

Besides that, I guess the local variables are final. So a value has to be assigned to them.

it is not right.

If they are final, how we can change the values for a local variable?

[Ravikanth kolli]

As AnoobKumar was talking about all local variables are not final.