Indeed, for the time tabling example there is no Java code. Since this is about a constraint programming example you are likely better off to ask your question on one of the CP Forums (I suggest the OPL related one).
Do you just want to load .mod file into Java and solve it or do you want to dynamically build up the model? In the first case opl/examples/opl_interfaces/java/oplrunsample should tell you waht to do. This provides Java code that loads and solves a .mod file.
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