I apologize -- I believe I had screwed up the various references to the newly installed JDK that resulted in a mixture of references to both the 121 release and the 111 release that likely caused the error.
After reviewing the JAVA_HOME declaration, the eclipse.ini vm entry, the Java / Installed VM settings, and the eclipse launcher JRE setting and ensuring they all pointed to the same JDK installation location, the problem has gone away.
Thank you all for trying to help. I'll try to remove any old remnant JDK installations to ensure only one is active.