Currently JUCE include guard macros look like JUCE_RANDOMACCESSFILE_JUCEHEADER
This goes against the specifications. User defined identifiers should not start with an underscore, or worse a double underscore. I suggest JUCE_RANDOMACCESSFILE_H_INCLUDED since this is the boost style. It also reads better when you use it in a conditional compilation expression:
#ifdef JUCE_RANDOMACCESSFILE_H_INCLUDED
// some code that depends on RandomAccessFile being available
#endif