Fast networks like InfiniBand are important for large-scale applications and large data analysis. Current InfiniBand hardware offers bandwidths of up to 200 Gbit/s with latencies of less than two microseconds. While it is mainly used in high-performance computing, there are also some big-data analysis applications that benefit from it. In addition, some cloud vendors offer instances equipped with InfiniBand hardware. While many big-data processing and analysis frameworks are written in the Java programming language, the Java Development Kit does not provide native support for InfiniBand hardware. For this purpose, we are developing neutrino, a network library that provides convenient and efficient access to InfiniBand hardware in Java. It supports both InfiniBand message passing and remote direct memory access, is implemented using the Java Native Interface and can be used with any Java Virtual Machine. In addition, it offers the possibility to access native C structures via a specially developed proxy system. This enables the developer to use the full functionality of the InfiniBand hardware.