Do you mean "override" or "overload"? It is not clear from the context which
standard term you intend.

The three seemingly overloaded methods you show cannot be overloads because of
"type erasure". That means that two methods whose signatures differ only in
the "generic part" really have the same signature. Two methods with the same
signature cause a "Duplicate method" compilation error.

Does each method perform a different algorithm depending on the List's base
type? If so, your answer might be inheritance and overriding the method:

public interface Tempus<T>
{
  public void temp( List<T> x );
}

public class StringTempus implements Tempus<String>
{
  public void temp( List<String> x )
  {
   ...
  }
}

public class IntegerTempus implements Tempus<Integer>
{
  public void temp( List<Integer> x )
  {
   ...
  }
}

Or, it may be that you are performing essentially the same list operation
independent of type, in which case you just declare a generic type:

public class TempusImpl<T> implements Tempus<T>
{
  public void temp( List<T> x )
  {
   ...
  }
}

Note that both approaches can coexist.

- Lew