since fe days I got problem with MySQL connection, it returns me some Java error: java.lang.AbstractMethodError: com.mysql.jdbc.Connection.isValid(I)Z. My current JDBC driver is 5.1.35. I've changed it to 5.1.39 and later to 6.0.4 but problem still occurs. Connection works properly, I see all tables etc. just during executing query like SELECT, INSERT etc. it returns taht error. Thanks in advance for all replies.