JEP is exactly the same thing as Python’s PEP, it really only changes the letter, until the definition is the same "Java Enhacement Proposal", and the use process is almost identical. Of course each community has its own way, its own criteria of what is good, how to write (how to format, which sections, etc.), who can participate in what way, etc. but the function is the same. In fact it is a process prior to what already existed the JCP (Java Community Process) which is the final step that all JEP goes through if it changes something in the technology (I don’t know the details, but what only recommends users follow, type PEP 8, does not go to JCP), anyway is something more informal, as shows Wikipedia.
The document is more visible, but both are a process, more than a document.
The JEP-1 explains better :P