Default Values

In Java, different types of variables have different default values when they are not explicitly initialized. Here are the default values for each type:

1. Primitive Data Types

   • byte, short, int, long: 0

   • float, double: 0.0

   • char: '\u0000' (null character)

   • boolean: false

2. Reference Data Types

   • For reference types (objects), the default value is null, meaning they do not refer to any object in memory.

3. Local Variables

   • Local variables must be explicitly initialized before they are used. They do not have default values. Compilation error will occur if not initialized and tried to use.

4. Static and Instance Variables

• If they are not explicitly initialized, they are automatically initialized with their default values. Non-static - Non local variables will also be initialized.

public class Application {
    static int i1;
    static Integer i2;
    public static void main(String[] args) {
        System.out.println(i1); // 0
        System.out.println(i2); // null
    }
}