The role of final in java

Final is used in Java to restrict access and modification to ensure program stability and security. Specific functions include: ① Classes cannot be derived as subclasses; ② Methods cannot be overridden; ③ Variable (constant) values ​​cannot be changed.

The role of final in Java

In Java, the final keyword is An important modifier used to restrict access and modification of classes, methods and variables.

Class

• Declaring a class as final means that no more subclasses can be derived from the class. This helps ensure that the behavior of the class is not changed accidentally.

Method

• Declaring a method as final means that the method cannot be overridden (overridden) by subclasses. This ensures that the behavior of the method does not change and is safe to call in subclasses.

Variables

• final variables are called constants, their values ​​are determined at compile time and cannot be changed during program execution.

Function

• Immutability: Final classes, methods and variables cannot be changed, thus ensuring the stability of the program Stability and security.
• Performance optimization: Since the value of the final variable is known at compile time, the compiler can optimize it to improve program performance.
• Safety and Reliability: The final modifier provides additional security against accidental or malicious modifications, thereby improving the reliability of the program.
• Clarify the intention: Using final indicates the developer's intention that the element should not be modified, which helps to enhance the readability and maintainability of the code.

Example

final class:

final class ImmutableClass {
    // ...
}

final method:

public final void printMessage() {
    // ...
}

final variable:

final int NUM_ELEMENTS = 10;

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