To reproduce:

1. Right-click on a directory in the Explorer and select New->Classes->Class.
2. Enter new name and press "Next >".
3. In the dialog for setting superclass and interfaces, click "Next >".
4. In the dialog for overriding methods, click "Next >".
5. In the dialog for adding new field click "Next >".
6. In the dialog for adding new methods:

    - add method a()
    - try to add method a(String)

    It is difficult - when you fill-in method name and try to add a parameter,
    the wizard complains about the duplicite method name. So you have to
    change the method name to something else, add the parameter(s) and then
    change the method back to 'a'.

    Another workaround - first add method a(String), then add method a()
    - but this is just a workaround.