For accelerator beam commissioning, script language is very powerful, especially in the early stage of commissioning, to create and modify applications quickly and iteratively. A high-level application framework based on script language, J-PARC Commissioning Environment (JCE), has been developed. JCE is capable of device control via EPICS, beam transport simulation with the XAL online model, GUI components, mathematical functions, and so on, which are flexibly and seamlessly combined in the script. A Mathematica style of language ("SAD script") is adopted, which was originally defined in "SAD" framework in KEK and has been successfully used for accelerators such as KEKB. However, SAD is implemented in complex FORTRAN code with interlaced parser parts and function parts. To overcome such problems, we have constructed JCE framework in Java, whose implementation is independent of SAD. A special care is taken to clearly separate the parser part from actual function parts, and to document the codes. Thus modularity of the architecture, code understandability, and extensibility are dramatically improved. JCE has been utilized successfully for beam commissioning of J-PARC linac.