Generic method invocation with <T>

Question

I have a problem with understanding such generic method invocation:

object = ObjectGenerator.<T> getObject(objectName);

Here comes a context for above situation:

class GenClass<T> {

   private T object;

   // ... some code

   public void initObject(String objectName) {
      object = ObjectGenerator.<T> getObject(objectName);
   }
}

class ObjectGenerator {

   public static <T extends Object> T getObject(String name) {
      // some code
      return someObject;
   }
}

The question is what role plays <T> before getObject(objectName) invocation?

Answer 1

Note: in the specific example you have given, ObjectGenerator.getObject(objectName); should compile fine.

In some situations, the type inference mechanism can't resolve the fact that in:

T object;
object = ObjectGenerator.getObject(objectName);

the returned type should be T. In such a case, you need give the compiler a little help by explicitly indicating the return type you expect.

Here is a contrived example where you need to explicitly specify the generic type:

class Example {
    public static <T> List<T> m1() {
        return m2(Arrays.<T> asList()); //Arrays.asList() would not compile
    }
    public static <T> List<T> m2(List<T> l) {
        return l;
    }
}