The TLA+ model-check task in Evergreen has started failing with:

Exception in thread "main" java.lang.NoSuchMethodError: java.lang.String.strip()Ljava/lang/String;
  at tlc2.TLC.handleParameters(TLC.java:750)
  at tlc2.TLC.main(TLC.java:245)

This is because we use the default java on the command line, which is Java 8 on the Ubuntu 18.04 builder machines, and the TLC model-checking tool has begun to require Java 11. I'm not sure this is intentional, I've filed a bug: https://github.com/tlaplus/tlaplus/issues/462

In any case, use Java 11, which is installed in /opt.