Player UUID cannot be null

[paul-eff]

Description: When running the converter, it crashes, telling me a player UUID cannot be null.

Error Text:
[XX:YY:ZZ][ERROR] - Player UUID cannot be null. Exception in thread "main" java.lang.IllegalArgumentException: Player UUID cannot be null. at me.pauleff.Player.<init>(Player.java:41) at me.pauleff.ConverterV2.fetchUsercache(ConverterV2.java:83) at me.pauleff.ConverterV2.preCheck(ConverterV2.java:106) at me.pauleff.ConverterV2.convert(ConverterV2.java:123) at me.pauleff.Main.main(Main.java:52)

Explanation: This happens when a Minecraft server was run in online-mode set to both, true and false, somewhere in the past. This results in both, the online and offline UUIDs, for all players that joined to be generated. Currently the converter can only handle conversion in one direction and will therefore crash when facing the wrong kind of UUID.

Resolution:
Short term: Catch the error, and inform the user.
Long term: Catch the error and handle the file conversion and file conflict accordingly.

What can you do right now: Look at this issue to get a general sense for what to do.