In Java, what is the difference between this.method() and method()?

Question

Is there any difference between calling this.method() and method() (including performance difference)?

Answer 1

The only time it matters is if you are using OuterClass.this.method() e.g.

class OuterClass {     void method() { }      class InnerClass {         void method() {             OuterClass.this.method(); // not the same as method().         }     }  } 

Answer 2

There is absolutely no difference between these constructs and the generated bytecode will be exactly the same, hence no performance impact. this is resolved during compilation if not explicitly defined.

The only reason for using explicit this is readability - some people find it easier to read because this suggests that this is an instance method of current object.

Also please note that if method() is static, using this is discouraged and misleading.

private static void method() { }  private void foo() {     this.method();    //generates warning in my IDE for a reason } 

And in this case it will also have no effect on performance.