Java中的最终变量

在Java中，我们可以在变量、方法和类中使用 final 关键字。当 final 关键字与原始数据类型（如 int、float 等）的变量一起使用时，变量的值不能更改。

示例 1： final 与原始数据类型的用法

Java

// Java Program to illustrate Use of Final Keyword
// With Primitive Datatypes
 
// Main class
class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
 
        // Final primitive variable
        final int i = 10;
        i = 30;
 
        // Error will be generated above
    }
}

输出：

现在您一定想知道如果我们确实使用 final 关键字非原始变量会怎样，让我们在示例的帮助下探索与上面所做的相同的事情。

Note: Non-primitive variables are always references to objects in Java, the members of the referred object can be changed. final for non-primitive variables just means that they cannot be changed to refer to any other object.

示例 2： final 与原始数据类型的用法

Java

// Java Program to illustrate Use of Final Keyword
// With Primitive Datatypes
 
// Class 1
class Helper {
    int i = 10;
}
 
// Clss 2
// main class
class GFG {
 
    // Main driver method
    public static void main(String args[])
    {
 
        final Helper t1 = new Helper();
        t1.i = 30; // Works
 
        // Print statement for successful execution of
        // Program
        System.out.print("Successfully executed");
    }
}

输出

Successfully executed