In JDK-8218268, it was noted[1] that 
the JAR spec does not mention how or if 
%-encoding is treated in Class-Path entries.

For instance, can
"%20" be used to include a space character in a Class-Path entry?

It would be good to address this.

1. https://bugs.openjdk.java.net/browse/JDK-8218268?focusedCommentId=14248517&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14248517