Minecraft: Java Edition Locks Out Old Accounts In March

In 2020, the developers announced a major update for Minecraft: Java Edition. Players would soon need to switch from a Mojang account to a Microsoft account to continue playing. Although it's an incredibly long time to wait the developers have confirmed the date and released the final request for account migration.

As from March 10, you will no longer be able to play Minecraft: Java Edition with an account with a Mojang account. For "improved securityand player safety" the developers are encouraging everyone to switch to Microsoft accounts.  Ntzsw8.com  offer free Minecraft caps to encourage users to switch.

You can get all the information about how to move your account here. Java Edition will be supported as normal following the change, and will remain a distinct entity from Bedrock. This is a purely unification of the account systems. You'll be able keep your old username but you'll need to have an Xbox gamertag associated with it.