What is final in java

The final keyword in Java represents a modifier, specifying that a variable, method or class cannot be changed. It includes the following usage: 1. Variables cannot be changed; 2. Methods cannot be overridden by subclasses; 3. Classes cannot be inherited. Using final provides immutability, performance, and security benefits, but also limits flexibility and reduces readability.

final in Java

In Java, final is a keyword that represents a modifier, used to specify Variables, methods, or classes cannot be changed. It has the following uses:

1. final variable

• makes the variable unchangeable and cannot be modified again once assigned.
• Can only be initialized at declaration time or in the constructor.
• Constants are usually decorated with final to ensure that their value remains unchanged throughout the program.

2. Final method

• Prevents the method from being overridden by subclasses.
• is used to ensure that method behavior is consistent throughout the inheritance hierarchy.
• Typically used to implement immutable classes or ensure that critical methods are not accidentally changed.

3. Final class

• Prevents the class from being inherited.
• is usually used to represent a final, non-extensible class.
• For example, the String class is final because its behavior is fully defined and does not require further extension.

Advantages

Using final provides the following benefits:

• Immutability: Ensures that the variable or Objects remain unchanged throughout the program, improving security.
• Performance: For immutable variables, the compiler can optimize because there is no need to check whether they have been modified.
• Security: Prevent accidental modification of key data and improve the robustness of the program.

Disadvantages

There are also some disadvantages to using final:

• Limited flexibility: Cannot be used in Later modification of final variables or methods may limit the flexibility of the program.
• Readability: May make the code harder to understand, especially for people who are not familiar with the meaning of final.

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