Generic method in Java without generic argument

Question

In C# I can do actually this:

//This is C#
static T SomeMethod() where T:new()
{
  Console.WriteLine(\"Typeof T: \"+typeof(T));
  return new T();
}
         


        

Answer 1

In Java, generics are compile-time only data, which are lost at run time. So, if you called a method like that, the JVM would have no way of knowing what T.class was. The normal way to get around this is to pass a class instance object as a parameter to the method, like this:

public static  T fromXml(Class clazz, String xml) {
  try {
    JAXBContext context = JAXBContext.newInstance(clazz);
    Unmarshaller um = context.createUnmarshaller();
    return (T)um.unmarshal(new StringReader(xml));
  } catch (JAXBException je) {
    throw new RuntimeException("Error interpreting XML response", je);
  }
}

fromXml(SomeSubObject.class, "");