The new format for the -Xpatch value is <module>=<file>(:<file>)* where <file> is an exploded directory or JAR file.

The -Xpatch option can be repeated. For now, the launcher will "communicate" the value of the -Xpatch options via the system properties jdk.launcher.patch.<n> where <n> starts at 0.

For transition purposes then we should allow the value of jdk.launcher.patch.0 be the old format <dir>(:<dir>)*

The library code will do a lot of validation of the -Xpatch values and so it should be possible for the VM to skip some of it.