how i can fix this:

concet errorjava.lang.ClassNotFoundException: com.mysql.jdbc.Driver concet errorjava.lang.ClassNotFoundException: com.mysql.jdbc.Driver Exception in thread "pool-1-thread-1" java.lang.NullPointerException at DataBais.DBFunction.getAdminDataByID(DBFunction.java:51) at Control.AdminCont.login(AdminCont.java:102) at view.LoginFram$4.run(LoginFram.java:190) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)