Question

// signatures of the reset method at //1 and //2 after erasure will be different
// then why don't they overload?

public class Test<T>{
    public static void main(String[] args) { 
        WordBox<String> city = new WordBox<String>("Skogland"); 
        city.reset("waiting");  // error: ambiguous 
    }
}


class Box <T> { 
    private T theThing; 
    public Box( T t) { theThing = t; } 
    public void reset( T t) { theThing = t; } //1  
} 

class WordBox< S extends CharSequence > extends Box< String > {
    public WordBox( S t)    { super(t.toString().toLowerCase()); }
    public void reset( S t) { super.reset(t.toString().toLowerCase()); }  //2
}

Answer 1

java.lang.String extends CharSequence, so calling city.reset("waiting") matches both WordBox.reset(S extends CharSequence) and Box.reset(String).

To fix the problem, you should either ensure WordBox.reset() accepts the same type as Box.reset(), in which case WordBox.reset() overrides Box.reset(), or, conversely, make sure WordBox.reset() accepts a type that does not overlap with Word.reset(), in which case WordBox.reset() overloads Box.reset(). In the example you give, I get the feeling you’d probably want WordBox.reset() to override Box.reset().