Android applications can have part of their components developed in a native language, such as C or C++. Developers, using the Native Development Kit, pack inside each application a shared library holding the native implementation of a subset of its methods. The Java Native Interface (JNI) allows each native method to interact directly with the rest, by providing a means to create or update Java objects, call Java methods, and several other operations. Two fundamental reasons lead to its integration: native programs have better performance, a key factor given Android’s limited hardware, and offer the possibility to reuse tested and optimized native libraries.