When Notes 14 FP2 came out, I made a blog post detailing a change that HCL made to the JRE classpaths that Designer uses for compilation. Specifically, since jvm/lib/ext is not present in newer Java versions, people had found that they manually had to add JARs from ndext to the JRE to get the same sort of "local JAR" behavior from previous versions. HCL "fixed" this by making it so that Designer adds all of the JARs in ndext to the compiling JRE, which sort of fixed the problem. It had the unfortunate side effect, though, of adding the various contaminants present in the Notes JVM to the classpath, particularly Poi and (in that post's case) the ancient Servlet spec.

In that post, I explained how to fix it. However, I hadn't yet noticed that it's not just that Designer does this once, but rather that it does it every time you launch, re-breaking compilation if your code runs afoul of this. Since then, I found a workaround that seems to stick, so it's worth documenting here.

Whatever code re-mangles the classpath does it specifically to the one named "jvm", so what I do now is go to Preferences - "Java" - "Installed JREs" and add a new definition for the same path but with only the core runtime package and a distinct name:

If you have any local JARs you do want to include, add them here.

Then, I mark that JRE as the default:

With this so marked, it will (at least in my experience) stick as your default across launches and you will be blessedly free from this particular excessive zeal on Designer's part.