Java kernel stopped recognizing identifiers defined in another cell

I'm having a truly weird problem, and what makes it even more weird is that, an hour ago, it was working just fine. It has just stopped working for no apparent reason. When I'm in a Java notebook, if I define something in one cell (and execute that cell, of course), and then access that thing from another cell, I get the "Cannot find symbol" error. For example, if in a particular cell I define `int myInt = 343;`, and then in another cell try to print it with `System.out.println(myInt);`, I get a `Cannot find symbol` error for `myInt`. I'm using beakerX version 1.3.0. I've tried restarting the kernel, and even restarting Jupyter, but the problem persists. What's really strange is that, until a particular moment it was working just fine, and from the very next moment, it just stopped working, for no apparent reason. This makes the Java kernel completely un-usable for me. Please help.