I was running into CODETOOLS-7902421. But that I've only figured out after I've worked around it. The first step was to get latest jcheck via the link from the project page[1], currently pointing to:

https://hg.openjdk.java.net/code-tools/jcheck/dist/raw-file/tip/jcheck.py

That's not the latest version though. The link should be:

https://hg.openjdk.java.net/code-tools/jcheck/raw-file/tip/jcheck.py

The link text is "latest version of jcheck.py" in section "Running jcheck in your own repositories", numbered entry 1.

Reproducer:

$ curl -s https://hg.openjdk.java.net/code-tools/jcheck/raw-file/tip/jcheck.py | grep inspect
import sys, os, re, urllib, urllib2, json, inspect
        if len(inspect.getargspec(context.changectx.__init__).args) == 4:

As expected.

$ curl -s https://hg.openjdk.java.net/code-tools/jcheck/dist/raw-file/tip/jcheck.py | grep inspect
<nothing>

NOT expected. Doesn't have fix for CODETOOLS-7902421 :(

[1] https://openjdk.java.net/projects/code-tools/jcheck/