Welcome to the Java Programming Forums
The professional, friendly Java community. 21,500 members and growing!
The Java Programming Forums are a community of Java programmers from all around the World. Our members have a wide range of skills and they all have one thing in common: A passion to learn and code Java. We invite beginner Java programmers right through to Java professionals to post here and share your knowledge. Become a part of the community, help others, expand your knowledge of Java and enjoy talking with like minded people. Registration is quick and best of all free. We look forward to meeting you.
>> REGISTER NOW TO START POSTING
Members have full access to the forums. Advertisements are removed for registered users.
LinkBack URL
About LinkBacks
Still don't understand what the 'this' keyword does
For the life of me I'm confused about the purpose of the 'this' keyword. I've read the bit in "Head First Java" but I still don't get it. What does it do, and why would anyone want to use it. The few pages or so in the book just don't make sense to me. Can someone offer a clear(er) explanation?
Re: Still don't understand what the 'this' keyword does
The this keyword is a reference to the instance of a class where code is being executed from within a method in that class.
Normally it is not required to code this as the compiler assumes its presence.
The one time it is needed is when a variable is declared within a method with the same name as a variable declared at the class level.public class TestThis { int aVar; // class level private void aMethod(int aVar) { // Argument with same name this.aVar = aVar; // copy arg to class instance variable } public static void main(String[] args) { TestThis tt = new TestThis(); tt.aMethod(12); System.out.println("aVar="+ tt.aVar); } }
If you don't understand my answer, don't ignore it, ask a question.
Re: Still don't understand what the 'this' keyword does
'This' keyword is used to refer instance variable of current class or you can say, it returns the current class instance. It invokes the current class constructor/method. It pass an argument in method/constructor call. We use 'this' keyword to remove the confusion between the class attributes and parameters with the same name.
Re: Still don't understand what the 'this' keyword does
There are many uses of the Java "this" keyword. In Java, the "this" keyword is the reference variable that refers to the current object.
Usage of Java "this" keyword, 6 usages of java this keyword.
1.) the "this" keyword can be used to refer to the current class instance variable.
2.) the "this" keyword can be used to invoke the current class method implicitly.
3.) the "this" keyword can be used to invoke a current class constructor.
4.) the "this" keyword can be used to pass as an argument in the method call.
5.) the "this" keyword can be used to pass as an argument in the constructor call.
6.) the "this" keyword can be used to return the current class instance from a method.
If you want to understand the working of 'this' keyword using program then you can mention it in replying.
Reply With Quote