Java channel access libraries JCA and CAJ have been commonly used for device control applications in Java. However, they have instability of performance and vulnerability of the code implementations. To overcome the problems, a new compact Java channel access library, JCAL (Java Channel Access Light library) has been developed. The library is so far limited to the channel access client functionalities and no channel access repeater has been implemented. A special care is taken to design the architecture in order to keep thread safety and robustness of the codes. The main part of the library works in a single thread (the inner thread), with outer threads for the monitor function and for the call-back function of a channel. By taking such a simple and well-defined design, robustness of the codes is realized. The bench mark tests in the real J-PARC control room environment have been carried out and compared to JCA and CAJ, which show comparable performance. An adapter library has been also implemented to easily plug in JCAL to existing Java applications using JCA or CAJ.