String concatenation

[Florian Jedamzik]

Hello there;)

I am currently working my way through different Practice Questions for the OCA Exam.

I recently got this question:

Given:

class StringExercise {

        public static void main(String[] args) {

                 String s = "Hello";
                 s.concat(" World");
                 s.toLowerCase();
                 System.out.println(s);
         }

}

Then it was asked how many objects have been created here?

The right answer was 4, but I am not quite sure why.

Am I right, that the first String-Object is created here:   String s = "Hello"; //the Object is "Hello"

Then, the second String-Object is created here:   s.concat(" World");         //the Object is " World"

Also, the third String-Object ist created here:   s.concat(" World");            //the Object is "Hello World"

At last, the fourth String-Object is created here:   s.toLowerCase();           //the Object is "hello world"

The System.out.println(s) only prints out "Hello" as String is immutable, right?

Kind regards
Florian

[Henry Wong]

Florian Jedamzik wrote:
At last, the fourth String-Object is created here:   s.toLowerCase();           //the Object is "hello world"

The String Object is actually "hello" created from this line, but the rest are correct.

Henry

[Florian Jedamzik]

Thanks;)