Differences Between final, finally, and finalize in Java

Do final, finally and finalize keywords have the same function? Explain.

The keywords final, finally, and finalize are often confused due to their similar names, but they serve different purposes in programming, particularly in Java.

1. final:

   • In Java, final is a keyword that can be applied to variables, methods, and classes.
   • When a variable is declared as final, its value cannot be changed once it has been assigned. This means it is a constant.
   • When a method is declared as final, it cannot be overridden by subclasses.
   • When a class is declared as final, it cannot be subclassed. This is often used to prevent inheritance for security or design reasons.

   Example:

   final int x = 10; // x cannot be changed
   final void myMethod() { /* ... */ } // cannot be overridden
   final class MyClass { /* ... */ } // cannot be subclassed
   

2. finally:

   • finally is a block used in exception handling in Java. It is used in conjunction with try and catch blocks.
   • The code inside a finally block will always execute after the try block, regardless of whether an exception was thrown or caught. This is typically used for cleanup activities, such as closing resources.

   Example:

   try {
       // code that may throw an exception
   } catch (Exception e) {
       // handle exception
   } finally {
       // cleanup code, always executes
   }
   

3. finalize:

   • finalize is a method in the Object class that can be overridden to perform cleanup before an object is garbage collected.
   • It is called by the garbage collector when it determines that there are no more references to the object. However, its use is generally discouraged in favor of other resource management techniques, such as try-with-resources or explicit resource management.

   Example:

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

In summary:

• final is used to declare constants, prevent method overriding, and prevent class inheritance.
• finally is used in exception handling to ensure that certain code runs regardless of whether an exception occurred.
• finalize is a method for cleanup before an object is garbage collected, but its use is discouraged in modern Java programming.

Thus, while they share a common prefix, they have distinct functions and are used in different contexts.