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Explain the concept of a local variable in Java.
Explain the concept of a local variable in Java.
A local variable is declared inside the body of a method and can only be used within that method.
What is an instance variable in Java?
What is an instance variable in Java?
An instance variable is declared inside a class but outside the body of a method, and is not declared as static.
Define a static variable in Java.
Define a static variable in Java.
A static variable is declared with the 'static' keyword and can be shared among all instances of a class.
Can a local variable be defined with the 'static' keyword?
Can a local variable be defined with the 'static' keyword?
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How many copies of a static variable can be created?
How many copies of a static variable can be created?
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Study Notes
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.
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Description
Test your knowledge of Java variables with this quiz. Learn about the different types of variables, including local, instance, and static, and understand their usage within methods.
