In Java, final and static are two different modifiers that can be applied to variables, and they serve distinct purposes.

Final Variable

  • When a variable is declared as final, it means that its value cannot be changed after it has been assigned a value.
  • Once a final variable is assigned a value, attempting to reassign a new value to it will result in a compilation error.
  • final variables are often used to create constants or to ensure that a variable retains a constant value throughout its lifetime. public class Example { final int constantValue = 10; public void changeValue() { // Compilation error: cannot assign a value to a final variable // constantValue = 20; } }

Static Variable

  • When a variable is declared as static, it means that the variable is associated with the class rather than with instances of the class (objects).
  • There is only one copy of a static variable, regardless of how many instances of the class are created.
  • static variables are often used to represent class-wide information or shared data among instances of the class. public class Example { static int staticVariable = 5; public static void main(String[] args) { // Accessing a static variable System.out.println(Example.staticVariable); // Modifying a static variable Example.staticVariable = 10; } }

Combining final and static:

  • It is possible to use both final and static modifiers together for a variable. In this case, the variable becomes a constant that is associated with the class and cannot be changed.
   public class Example {
       static final int CONSTANT_VALUE = 42;

       public static void main(String[] args) {
           // Accessing a final static variable
           System.out.println(Example.CONSTANT_VALUE);

           // Compilation error: cannot assign a value to a final variable
           // Example.CONSTANT_VALUE = 10;
       }
   }

In summary, a final variable is one whose value cannot be changed once assigned, and a static variable is associated with the class rather than instances of the class.

They can be used independently or together, depending on the requirements of the program.