The JAR file specification has been updated to clarify what constitutes a valid entry for the `Class-Path` JAR Manifest Attribute. See the JAR file specification for further details.

Invalid entries are now ignored. Applications relying on invalid `Class-Path` entries may see a `ClassNotFoundException`. A system property has been added to aid in debugging the `Class-Path` attribute. When the `"jdk.net.URLClassPath.showIgnoredClassPathEntries"` property is set to `true`, invalid `Class-Path` entries will be printed to the console.