Why are some variables highlighted when debugging in eclipse?

Question

I have bright yellow highlight on some variable values in debug perspective. They are not being watched. (Cannot show image as <10 reps.)

Answer 1

It highlights variables whose values changed since the last step

So if I set the breakpoint inside a method, call it multiple times with different inputs, and resume repeatedly with F8, only the changed variables will be highlighted.

Try it out with:

public class Main {

    static Integer f(Integer i, Integer i2) {
        // Breakpoint here.
        return i + i2;
    }

    public static void main(String[] args) {
        Integer i0 = 0;
        Integer i1 = 1;
        Integer i2 = 2;
        Integer i3 = 3;
        f(i0, i1);
        // F8
        // None highlighted.
        f(i0, i1);
        // F8
        // i2 highlighted.
        f(i0, i2);
        // F8
        // i1 highlighted.
        f(i1, i2);
        // F8
        // Both highlighted.
        f(i3, i3);
    }
}

The appearance of the changed variables can be modified as discussed at: https://stackoverflow.com/questions/11728040/eclipse-variables-window-changed-value-color