Question

I’m trying to get an understanding of what the the java keyword this actually does. I’ve been reading Sun’s documentation but I’m still fuzzy on what this actually does.

Answer 1

The this keyword is a reference to the current object.

class Foo {     private int bar;      public Foo(int bar)     {         // the 'this' keyword allows you to specify that         // you mean 'this type' and reference the members         // of this type - in this instance it is allowing         // you to disambiguate between the private member         // 'bar' and the parameter 'bar' passed into the         // constructor         this.bar = bar;     } } 

Another way to think about it is that the this keyword is like a personal pronoun that you use to reference yourself. Other languages have different words for the same concept. VB uses Me and the Python convention (as Python does not use a keyword, simply an implicit parameter to each method) is to use self.

If you were to reference objects that are intrinsically yours you would say something like this:

My arm or my leg

Think of this as just a way for a type to say ‘my’. So a psuedocode representation would look like this:

class Foo {     private int bar;      public Foo(int bar)     {         my.bar = bar;     } }