What is the feature of this keyword in java?

Answer 1

this refers to the current object. It is often used in constructors to not mix up class attributes with parameters, e. g.:

class my class{
private int i;
public myClass (int i) {
this.i=i; // assigns the parameter i to
// class attribute i
}
}

Answer 2

it have current irration value

Answer 3

its a kind of local reference to variable inside particular function /method.