没有传递任何参数时，我应该在构造函数中使用关键字“ this”吗？

Question

I was wondering whether I should be using "this" in Java when no arguments are being passed in the constructor of a class.

private int id;

public ClassName() {
    this.id = -1;
}

OR

 private int id;

public ClassName() {
    id = -1;
}

Thank you for your time.

Answer 1

If there is no argument, then it's all the same. However it's always a good practice.

Answer 2

No, this in this case is optional. Only need it when the constructor is passed a parameter named id to avoid variable shadowing.

Answer 3

You shouldn't be doing either actually. You should initize that variable in the declaration.

If you have a more complex case, the principle of least redundancy applies: don't write it where it isn't required.