Grails: ClassNotFoundException: com.mysql.jdbc.Driver in WAR deployment - mysql

Question

This is an issue that just started happening recently and its only with specific projects and WAR deployment. I am not able to deploy a WAR file because I get the following exception
ERROR org.apache.tomcat.jdbc.pool.ConnectionPool - Unable to create initial connections of pool.
java.sql.SQLException: com.mysql.jdbc.Driver
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:254)
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:182)
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:712)
[.....]
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:348)
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)
Nothing in my project has changed since my last successful deploy (I verify with git) and I can run the project fine using Spring Boot.
The mysql-connector is in my gradle build
runtime 'mysql:mysql-connector-java:5.1.46' (I have also tried changing to compile)
I have the driver declared properly in my application.yml
dataSource:
pooled: true
jmxExport: true
driverClassName: com.mysql.jdbc.Driver
dialect: org.hibernate.dialect.MySQL5InnoDBDialect
username: ****
password: ****
environments:
production:
dataSource:
password: *****
dbCreate: none
url: jdbc:mysql://localhost:3306/myapp
I am using Intellij IDE and can confirm that the mysql-connector is listed in my classpath and when I explode my WAR file mysql-connector-java-5.1.46.jar is listed in my WEB-INF/lib
I have done multiple cleans and rebuilds of the project. I am really at a loss for what is happening and as mentioned its only specific projects. I have other grails projects with identical config setups and deploy just fine but a handful of others give me this error. Any ideas?
Tomcat: 7.0.70
Java: 1.8.0_91
MySQL: 5.6 and 5.7 (fails on both)
Grails: 3.3.1
Update:
So if I put my mysql jar in my Tomcat lib folder instead of my project lib folder then it works. So that proves that the JAR file is valid. When I put the JAR file back into the WEB-INF/lib folder of my app then it doesn't work. So it seems for some reason the JAR file is being ignored or not loaded when its packaged with my app. Again though, its just some apps. I have other apps that works just fine with the lib packaged with the app.

Answer 1

I'm sure. It's not issue of jar file.
You can check here in repo and here for all versions of MySQL connectors
Please verify your dependency runtime "mysql:mysql-connector-java:5.1.46"
Verify your system MySQL server user and password and dataSource username , password.
Verify your MySQL running fine with valid credentials.
Because ERROR org.apache.tomcat.jdbc.pool.ConnectionPool - Unable to create initial connections of pool. this error will come when MySQL is not running on system or invalid username password.
One more possibility of error:
If you have updated your MySQL version. It will try to connect securely.
So by you need to pass some parameters to URL mysql://localhost:3306/yourDb?autoReconnect=true&useSSL=false&useUnicode=true
Last option if you are not resolved problem:
Update your dependency and configuration with latest version.
Dependency for your reference:
runtime "mysql:mysql-connector-java:6.0.6"
and Application.yml
dataSource:
dbCreate: update
pooled: true
url: jdbc:mysql://localhost:3306/YourDb?autoReconnect=true&useSSL=false&useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC
driverClassName: com.mysql.cj.jdbc.Driver
dialect: org.hibernate.dialect.MySQL5InnoDBDialect
username: yourUsername
password: yourPassword
properties:
...
driverClassName have been changed in latest version.
Hope this will helps you.