Big Big Funky Question

Question

Hey people,
This might be a stupid question but I'm just wondering what variables in java are initialized to if they are even initialized. Are they initialized and to what? The data types I'm talking about are int,boolean,String,byte,char which are the ones I deal with most.

Answer 1

Variables don't have default values. Fields do.I thought I held the "Pedant of the Day"? award,
but I see that I've been usurped... ;o)We must revoke the archivist's award.
"[JLS section]4.5.3 Kinds of Variables
There are seven kinds of variables:
1. A class variable is a field declared using the keyword static within a class declaration (�8.3.1.1), or with or without the keyword static within an interface declaration (�9.3). A class variable is created when its class or interface is prepared (�12.3.2) and is initialized to a default value (�4.5.5). The class variable effectively ceases to exist when its class or interface is unloaded (�12.7).
2. An instance variable is a field declared within a class declaration without using the keyword static (�8.3.1.1). If a class T has a field a that is an instance variable, then a new instance variable a is created and initialized to a default value (�4.5.5) as part of each newly created object of class T or of any class that is a subclass of T (�8.1.3). The instance variable effectively ceases to exist when the object of which it is a field is no longer referenced, after any necessary finalization of the object (�12.6) has been completed.
3. Array components are unnamed variables that are created and initialized to default values (�4.5.5) whenever a new object that is an array is created (�15.10). The array components effectively cease to exist when the array is no longer referenced. See �10 for a description of arrays.
4. Method parameters (�8.4.1) name argument values passed to a method. For every parameter declared in a method declaration, a new parameter variable is created each time that method is invoked (�15.12). The new variable is initialized with the corresponding argument value from the method invocation. The method parameter effectively ceases to exist when the execution of the body of the method is complete.
5. Constructor parameters (�8.8.1) name argument values passed to a constructor. For every parameter declared in a constructor declaration, a new parameter variable is created each time a class instance creation expression (�15.9) or explicit constructor invocation (�8.8.5) invokes that constructor. The new variable is initialized with the corresponding argument value from the creation expression or constructor invocation. The constructor parameter effectively ceases to exist when the execution of the body of the constructor is complete.
6. An exception-handler parameter is created each time an exception is caught by a catch clause of a try statement (�14.19). The new variable is initialized with the actual object associated with the exception (�11.3, �14.17). The exception-handler parameter effectively ceases to exist when execution of the block associated with the catch clause is complete.
7. Local variables are declared by local variable declaration statements (�14.4). Whenever the flow of control enters a block (�14.2) or for statement (�14.13), a new variable is created for each local variable declared in a local variable declaration statement immediately contained within that block or for statement. A local variable declaration statement may contain an expression which initializes the variable. The local variable with an initializing expression is not initialized, however, until the local variable declaration statement that declares it is executed. (The rules of definite assignment (�16) prevent the value of a local variable from being used before it has been initialized or otherwise assigned a value.) The local variable effectively ceases to exist when the execution of the block or for statement is complete."