EDIT: my Jira search is weak; this is a duplicate of MC-67961. Feel free to close.
If a server with compression already enabled tries to modify the compression threshold, the client drops to the Connection Lost screen with "Internal Exception: java.lang.ClassCastException: gp cannot be cast to gq".
This exception originates inside method "gr.a(int)", which appears to have a copy/paste error where it performs an "instanceof" check and cast on different objects.
The error was produced using a custom server but it is certainly a client bug.
Linked issues
Comments 2
hello i have a problem for get in a server in other server insidie, i can get in the sever but next have 13 servers, and one day for other, show this problem and i dont understand how fix i see the problem is the user not server i now some language Java, i see the fix but i dont know where i change, i have contat the op servers, sorry i dont know how i resolve the problem
...also, your Java is outdated.