This is a very basic example viewer using the new JNI classes. The build system is a bit incomplete. You need gradle 2.10 (exactly!). Copy the libmupdf_java.so file from the original viewer build: $ cd ../viewer && ndk-build $ cp ../viewer/libs/armeabi-v7a/libmupdf_java.so mupdf/libs/armeabi-v7a/libmupdf_java.so Build and install on device: $ gradle-2.10 installArmDebug