The final keyword is crucial for several reasons:

• Immutability: Making a class or variable final can be a crucial aspect in creating immutable structures in Java, similar to the String class.
• Thread Safety: Final variables are inherently thread-safe as their state cannot change once set.
• Maintenance and Operation Safety: Final methods prevent subclasses from altering base class logic, which can be crucial for maintaining consistent behavior in inherited methods.

Examples of the ‘final’ Keyword in Use

Here are some examples to illustrate how final can be used in Java programming:

// Final variable example
final int LIMIT = 5;

// Final method example
public final void display() {
  System.out.println(This method cannot be overridden.);
}

// Final class example
public final class Example {
  // Implementation goes here
}

Differences Between final, const, and immutable

It’s important to distinguish between final, const (from other languages like C++ or Dart), and immutable. Java’s final keyword is not necessarily about immutability but about preventing reassignment and inheritance. An object reference declared as final can still have an object that internally changes its state – the reference itself just cannot point to a different object.

Comprehensive Use Cases and Best Practices

Using the final keyword efficiently requires understanding specific scenarios and practices:

• Security-related classes often declare themselves as final to prevent malicious behaviors via subclassing.
• In high-concurrency scenarios, final variables provide a guaranteed thread-safe shareable state without requiring synchronization.
• Use final methods when providing critical functionality that should not be altered by any inheriting classes.

Conclusion

Understanding and using the final keyword appropriately in Java is essential for creating robust, secure, and maintainable code. It serves multiple purposes, from creating constants and immutable classes to making methods secure from overrides. Depending on the context, it provides significant advantages: