The mutation operators implemented in a mutation tool typically mutate the entire programs thoroughly and thus generate enormous number of mutants spread all over the programs. However, the complexity and difficulty level of methods implemented in a given program is less evenly distributed all over the program. Hence, the non-uniform distribution of complexity of methods in a program is an indication of testing efforts required for each method. We introduce partial mutations where only the complex parts of the programs are mutated instead of the entire programs. Paraμ is a mutation tool for Java programs enabling partial mutations. In addition to the class mutation, Paraμ implements concurrency mutation operators to address the recent advances in multicore systems and hence mutation testing of parallel and multi-threaded programs. Furthermore, Paraμ allows higher-order mutations by which the users are allowed to specify the order and the types of mutation operators and thus perform a combinatorial higher-order mutation testing.