The majority of mainstream programming languages support parallel computing via extended libraries that require restructuring of sequential code. Library-based features are portable, but tend to be verbose and usually reduce the understandability and modifiability of code. On the contrary, approaches with language constructs promote simple code structures, hide the complexity of parallelization and avoid boilerplate code. However, language constructs normally impose additional development concepts and compilation requirements that may sacrifice the ease-of-use and portability. Therefore, frameworks that offer simple and intuitive concepts and constructs that are recognized by the standard compilers of a language can gain priority over other approaches. In this paper we discuss @PT (Annotation Parallel Task), a parallel programming framework that proposes Java annotations, standard Java components, as its language constructs. @PT takes an intuitive object-oriented approach on asynchronous execution of tasks, and has a special focus on GUI-responsive applications. This paper presents the annotation-based programming interface of the framework and its fundamental parallelization concepts. Furthermore, it studies @PT in different parallel programming patterns, and evaluates its efficiency by comparing @PT with other Java parallelization approaches in a set of standard benchmarks.