Difference between final, finally and finalize()

final:

• final is a keyword
• final is used to apply restrictions on class, method and variable
• final class cannot be inherited
• final method cannot be overriden
• final variable value cannot be changed

1. class FinalExample {
2. public static void main(String[] args) {
3. final int x = 100;
4. x = 200;// Compile Time Error
5. }
6. }

finally:

• finally is a block
• finally block always execute, whether exception is handled or not
• in one scenario finally block doesn't execute is System.exit(0);

1. class FinallyExample {
2. public static void main(String[] args) {
3. try {
4. int x = 300;
5. } catch (Exception e) {
6. System.out.println(e);
7. } finally {
8. System.out.println("finally block is executed");
9. }
10. }
11. }

finalize():

• finalize() is a method
• finalize is used to perform clean up processing just before object is garbage collected

1. class FinalizeExample {
2. public void finalize() {
3. System.out.println("finalize called");
4. }
5. public static void main(String[] args) {
6. FinalizeExample f1 = new FinalizeExample();
7. FinalizeExample f2 = new FinalizeExample();
8. f1 = null;
9. f2 = null;
10. System.gc();
11. }
12. }