NullPointerException

[Emperor88]

This exception gets thrown on quite frequently:
Exception in thread "Thread-20" java.lang.RuntimeException: java.lang.NullPointerException
at com.mysql.jdbc.JDBC4Connection$1$1.run(JDBC4Connection.java:106)
Caused by: java.lang.NullPointerException
at com.mysql.jdbc.ConnectionImpl.abortInternal(ConnectionImpl.java:1229)
at com.mysql.jdbc.JDBC4Connection$1$1.run(JDBC4Connection.java:104)

I'm configuring HikariCP like this:
HikariConfig config = new HikariConfig();
config.setMinimumPoolSize(1);
config.setMaximumPoolSize(3);
config.setInitializationFailFast(true);
config.setDriverClassName("com.mysql.jdbc.Driver");
config.setJdbcUrl("jdbc:mysql://" + URL);
config.setUsername(USERNAME);
config.setPassword(PASSWORD);
config.setJdbc4ConnectionTest(true);
pool = new HikariDataSource(config);

Changing idle timeout value seems to influence the exception being thrown (but doesn't stop it from happening).
I'm probably doing something wrong, as I couldn't find simular problems when searching on google.

[brettwooldridge]

This thread indicates that it is a bug with the MySQL JDBC driver implementation of the Connection.isValid() method -- which is what HikariCP uses by default. I would recommend two things: first, make sure you are using the latest MySQL Connector/J version, and second change HikariCP to use query-based connection testing like this:

config.setJdbc4ConnectionTest(false);
config.setConnectionTestQuery("/* ping */ SELECT 1");

[Emperor88]

Thanks for the quick reply, updating the MySQL connector did the trick.

[MMuzaffar]

What Connector version you are using now?

[MMuzaffar]

I replaced com.mysql.jdbc_5.1.5.jar file with mysql-connector-java-8.0.11.jar in \WebContent\WEB-INF\lib folder and these exceptions gone.

[MMuzaffar]

This thread indicates that it is a bug with the MySQL JDBC driver implementation of the Connection.isValid() method -- which is what HikariCP uses by default. I would recommend two things: first, make sure you are using the latest MySQL Connector/J version, and second change HikariCP to use query-based connection testing like this:

config.setJdbc4ConnectionTest(false);
config.setConnectionTestQuery("/* ping */ SELECT 1");

I don't know where are these configs?