Java技术问询：能否将指定关键词定义为引用变量？this是否为引用变量？

1. Can we define the this keyword as a reference variable in Java? #

Absolutely not. this is a reserved keyword in Java—keywords are pre-defined with special meanings and can't be used as identifiers (like variable names, method names, or class names). If you try to write code like:

// This will throw a compilation error!
Object this = new Object();

The compiler will immediately flag it as invalid, since this can't be treated as a user-defined variable.

2. For the given Java code, can we say this is a reference variable? #

Let's first look at your code again:

public class Temp { 
    private int x = 3; 
    public void show() { 
        this.x = 4; 
        this.show(); // same as show(); 
    } 
}

The short answer is: No, this isn't a reference variable—but it does act as a reference to the current object instance.

Here's the breakdown:

• this is an implicit reference value that points to the object whose method is currently being executed. You can use it to access instance members (like this.x in your code) or call other instance methods of the same object (like this.show()).
• Unlike regular reference variables (which you can declare, assign, and reassign), you can never assign a new value to this (e.g., this = new Temp(); is illegal) or declare this as a variable. It's a built-in, fixed reference that's automatically available in every instance method.

So to be precise: this represents the reference to the current object, but it's not a user-definable or mutable reference variable.

内容的提问来源于stack exchange，提问作者Abhishek Dubey