Difference Between final, finally, and finalize() in Java

Difference Between `final`, `finally`, and `finalize()` in Java

In Java, the terms final, finally, and finalize() often confuse beginners due to their similar names. However, each has a very different purpose and use case. Let’s break them down in detail.

1. `final` Keyword

1.1 final Variable

final int MAX_AGE = 100;
// MAX_AGE = 90; // Compilation error

1.2 final Method

class Animal {
  final void sound() {
      System.out.println("Animal sound");
  }
}

class Dog extends Animal {
  // void sound() {} // Error
}

1.3 final Class

final class Constants {
  public static final double PI = 3.14159;
}

// class ExtendedConstants extends Constants {} // Error

2. `finally` Block

public class TryFinallyExample {
  public static void main(String[] args) {
      try {
          int data = 100 / 5;
          System.out.println(data);
      } catch (Exception e) {
          System.out.println("Exception caught: " + e);
      } finally {
          System.out.println("finally block executed");
      }
  }
}

Output

20
finally block executed

3. `finalize()` Method

protected void finalize() throws Throwable {
  // cleanup code
  super.finalize();
}

Example

public class FinalizeExample {
  protected void finalize() {
      System.out.println("Finalize method called");
  }

  public static void main(String[] args) {
      FinalizeExample obj = new FinalizeExample();
      obj = null;
      System.gc(); // Suggests GC
  }
}

Summary Table

Feature	final	finally	finalize()
Type	Keyword	Block	Method
Usage	Restrict modification	Exception handling cleanup	Garbage collection cleanup
Called by	Programmer	JVM during try-catch	JVM during GC
Modern Use	Recommended	Recommended	Deprecated

Conclusion

Understanding the difference between final, finally, and finalize() helps you write more secure and efficient Java code. Use them wisely according to their purpose.

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Understanding the difference between final, finally, and finalize() is essential for writing safe, clean, and interview-ready Java code. Explore these related Java fundamentals to strengthen your understanding of exception handling, memory management, and real-world coding practices.

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