Difference between initializing variables with null or 0 or "" [closed]

Question

Could anyone provide simple example when and where to declare null or 0 or "" while declaring variables in java? I went through some examples but didn't understand, so can anyone explain clearly with some simple examples?

Answer 1

• Class variables, instance variables, or array components are initialized for you _{(non-final ones)}, so there is no need to initialize them to false/null/0 (it will be redundant):

  Each class variable, instance variable, or array component is initialized with a default value when it is created (§15.9, §15.10):

• You need to initialize local variables though:

  Local variables are slightly different; the compiler never assigns a default value to an uninitialized local variable. If you cannot initialize your local variable where it is declared, make sure to assign it a value before you attempt to use it. Accessing an uninitialized local variable will result in a compile-time error.

• If you want an empty string for instance, use String myStr = "";