The Object Teams Blog

Just today Oracle helped me to become a “Guru” on Stackoverflow! How did they do it? By doing nothing.

In former times, I was periodically enraged, when Oracle didn’t pay attention to the feedback I was giving them during my work on ecj (the Eclipse Compiler for Java) – at least not the attention that I had hoped for (to be fair: there was a lot of good communication, too). At those times I had still hoped I could help make Java a language that is completely and unambiguously defined by specifications. Meanwhile I recognized that Java is at least three languages: the language defined by JLS etc., the language implemented by javac, and the language implemented by ecj (and no chance to make ecj to conform to both others). I realized that we were not done with Java 8 even 3 years after its release. Three more years later it’s still much the same.

So let’s move on, haven’t things improved in subsequent versions of Java? One of the key new rules in Java 9 is, that

“If [a qualified package name] does not name a package that is uniquely visible to the current module (§7.4.3), then a compile-time error occurs”.

Simple and unambiguous. That’s what compilers have to check.

Except: javac doesn’t check for uniqueness if one of the modules involved is the “unnamed module”.

In 2018 there was some confusion about this, and during discussion on stackoverflow I raised this issue to the jigsaw-dev mailing list. A bug was raised against javac, confirmed to be a bug by spec lead Alex Buckley. I summarized the situation in my answer on stackoverflow.

This bug could have been easily fixed in javac version 12, but wasn’t. Meanwhile upvotes on my answer on stackoverflow started coming in. The same for Java 13. The same for Java 14. And yet no visible activity on the javac bug. You need ecj to find if your program violates this rule of JLS.

Today the 40th upvote earned me the “Guru” tag on stackoverflow.

So, please Oracle, keep that bug unresolved, it will earn me a lot of reputation for a bright future – by doing: nothing 🙂

Edit: In 2020/04, Oracle dropped any plans to resolve the issue, meanwhile my answer on stackoverflow matured into a “Great Answer” with more then 100 upvotes.