Classpath generation (migrating from old to new)

Folks,

I have been given responsibility of migrating an mixed code project from the RHEL 6.10 system we are on to a RHEL 8.1 system. My main experience is more on the C/C++ side of the code base.

The old system was running Ant 1.7.1 on Java 1.7.0_201. The new system is running Ant 1.10.5 on Java 1.8.0_222.

The particular issue is the classpath generated. On the old system, the classpath included all the local user defined .jars, as well as a large number of jars from /usr/share/java, that were not specified in the build.xml file. The new system only has the local user defined jars. This leads to issues because we needed at least one of the /usr/share/java jars.

My question is : Why did Ant 1.7 include these jars ? Is there a config file hidden somewhere in the Ant installation that controls it ? And can I reproduce this behavior in Ant 1.10 ? Or do I need to start explicitly specifying these in the build.xml (after I determine what file was being used).

Thanks,
Dale Pennington.