[Java] Fix warning.

Author: mjpt777

sbe-tool/src/main/java/uk/co/real_logic/sbe/codec/java/MethodSelector.java

@@ -71,7 +71,7 @@ private Set<String> getSortedMethods(final Class<?> clazz, final Method[] method
  final GroupOrder order = clazz.getAnnotation(GroupOrder.class);
  if (order == null)
  {
- sortedMethods.put(clazz, Collections.<String>emptySet());
+ sortedMethods.put(clazz, Collections.emptySet());
 
  return Collections.emptySet();
  }