Can toString() method take an argument in Java?

Question

I tested this in eclipse, and it didn't give me any exceptions. However I wasn't able to specify the value x. Can toString() take an argument (I know that my example below isn't the greatest)?

Test.java

public class Test {

    public String toString(int x){
        return "Hey "+ x;
    }

}

Main.java

public class Main {
      public static void main(String[] args){

          System.out.println(new Test());


      }
}

It is useless. only toString() is usefull, because already used by other libraries. You could name it anotherToString() also ... — guillaume girod-vitouchkina, Dec 21 '15 at 11:36

Konstantin Yovkov · Accepted Answer · 2015-12-21T11:33:03.900

11

Can toString() take an argument?

Yes, and in this case you'll have an overloaded toString() method.

When invoking System.out.println(t), however, the Object#toString() will be invoked anyway (and you can verify that by checking the PrintStream#println(Object t) method's source).

In order to invoke your custom .toString() method, you have to do (for example):

System.out.println(t.toString(5));

edited Dec 21 '15 at 11:33

answered Dec 21 '15 at 11:30

Konstantin Yovkov

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Superb, that makes sense. Thank you! – aqibjr1 Dec 21 '15 at 11:32

score 4 · Answer 2 · edited May 23 '17 at 12:15

Yes, but in this case you won't be overriding the Object::toString method, just creating your own overloading.

Your method is valid

public String toString(int x) {
     return "Hey "+ x;
}

Check this question to clarify

To execute it this won't be valid because you will be calling Test.toString() not Test.toString(int):

System.out.println(new Test());

Create an instance and call your method:

Test t = new Test();
System.out.println(t.toString(10);

OUTPUT:

Hey 10

Can toString() method take an argument in Java?

2 Answers2