An analysis of the “final” keyword in Java

There are multiple purposes for the ‘final’ keyword in Java, as discussed below.

1. Final variables: When a variable is modified by ‘final’, it means that the variable can only be assigned once, making it a constant. Once assigned, it cannot be altered. For example:

final int x = 10;

1. Final method: When a method is marked as final, it means that the method cannot be overridden by a subclass. This can serve as a form of protection in certain situations, preventing subclasses from altering the implementation of a method in the superclass. For example:

public final void print() {
    System.out.println("Hello, World!");
}

1. When a class is labeled as final, it means that it cannot be inherited. This is typically used to designate core classes to ensure they are not modified or compromised. For example:

final class MyClass {
    // 类的实现
}

1. When a parameter is marked as final, it means that the parameter cannot be modified within the method. This can be used to protect the passed-in parameter from being accidentally altered. For example:

public void print(final String message) {
    System.out.println(message);
}

In general, the purpose of the final keyword is to restrict the modification of certain elements. It can be applied to variables, methods, and classes to ensure their immutability or uninheritability, thereby increasing the security and stability of the code.