Java Variables Quiz

Local Variable in Java

• A local variable is declared within a method, constructor, or block.
• Its scope is limited to the block of code where it is defined.
• Local variables must be initialized before use; otherwise, the compiler will throw an error.
• Not accessible outside the method or block in which they are declared.

Instance Variable in Java

• An instance variable is defined within a class but outside any method, constructor, or block.
• Each instance of a class has its own copy of instance variables; their values can differ across instances.
• Instance variables are initialized to default values (0, null, false) if not explicitly initialized.
• They can be accessed by all methods of the class.

Static Variable in Java

• A static variable is unique to the class itself rather than to instances of the class.
• Only one copy of a static variable exists, regardless of how many instances of the class are created.
• Static variables are shared among all instances, and they exist as long as the class is loaded in memory.
• Initialized only once, at the start of the execution of the program.

Local Variable with Static Keyword

• Local variables cannot be declared as static.
• The static keyword applies to the class level, not to the local context of methods or blocks.
• Attempting to declare a local variable as static results in a compile-time error.

Copies of Static Variable

• Only one copy of a static variable can be created per class.
• This single copy is shared among all instances of that class, maintaining a consistent value across all instances.