Initially this doesn't even compile
Let Eclipse fill in the missing pieces
You'll probably end up with something like this:
public class Complex {
    public Complex(int i, int j) {
        
        
    }
    public Complex add(Complex z2) {
        return null;
    }
    public long getRealPart() {
        // ???? Auto-generated method stub
        return -1;    }
    public long getImaginaryPart() {
        // ???? Auto-generated method stub
        return -1;
    }
}