Easy to use Java Sub-Command Manager (created for bukkit, could use in any software by changing CommandSender)
Create class named SubCommandManager.java and paste the content from https://github.com/luca-gg/SubCommandManager/blob/master/SubCommandManager.java.
In your command manager check if the arguments length is > 0, then pass arguments to your SubCommandManager and have fun with the returned state.
if (args.length > 0) {
var executionState = SubCommandManager.execute(commandSender, args);
switch (executionState) {
case NOT_FOUND:
commandSender.sendMessage(SUBCOMMAND_NOT_FOUND);
break;
case NO_PERMISSION:
commandSender.sendMessage(SUBCOMMAND_INSUFFICIENT_PERMISSIONS);
break;
case INVALID_ARG_LENGTH:
commandSender.sendMessage(SUBCOMMAND_INVALID_ARG_LENGTH);
break;
default:
}
}(dont copy and paste this code if you are using java8 like the most spigot programmers, you need to change var to SubCommandManager.SubCommandState)
Example subcommand can be found at https://github.com/luca-gg/SubCommandManager/blob/master/TestSubCommand.java.