A string method whose result is not kept

Predict the outputEasyJava only

Main.java

public class Main {
    public static void main(String[] args) {
        String s = "test";
        s.concat("ing");
        s.toUpperCase();
        System.out.println(s);
    }
}

What does it print?

Graded by exact match. Spaces at the ends of lines and blank lines at the end do not count.

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