Lucene Index Builder broken and Spring packages being identified as application packages

MTA builds an index of maven artifacts so that it can distinguish between standard java framework packages and application packages.
The Maven index contained erroneously Gradle modules for many Spring artifacts which resulted in missing artifacts in MTA's index and hence MTA was erroneously treating Spring libraries (3rd party packages) as application packages resulting in long execution times and an erroneously high volume of issues on the MTA reports.

Tried to create a new Lucene index version but the build failed due to:

[INFO] Caused by: java.io.IOException: Server returned HTTP response code: 501 for URL: http://repo1.maven.org/maven2/.index/nexus-maven-repository-index.properties
[INFO]     at sun.net.www.protocol.http.HttpURLConnection.getInputStream0 (HttpURLConnection.java:1894)
[INFO]     at sun.net.www.protocol.http.HttpURLConnection.getInputStream (HttpURLConnection.java:1492)
[INFO]     at java.net.HttpURLConnection.getResponseCode (HttpURLConnection.java:480)