Tomcat: java.sql.SQLException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader

Question

While running a web application on server I am getting the below exception:

Server Used : Apache Tomcat 8.5

Exception : java.sql.SQLException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader

I have tried lot of things including putting ojdbc6.jar in WEB-INF/lib folder, putting jar in apache tomcat lib folder,in build path of project i have manually added the jar, also based on google findings attempted few turnarounds which didn't worked out in my case.

From the perspective of a web application, class or resource loading looks in the following repositories, in this order:

1. Bootstrap classes of your JVM
2. /WEB-INF/classes of your web application
3. /WEB-INF/lib/*.jar of your web application
4. System class loader classes (described above)
5. Common class loader classes (described above)

I have the jar in /WEB-INF/lib/ folder.

Complete stack trace.

java.sql.SQLException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader:java.net.URLClassLoader@76ed5528;ClassLoader:ParallelWebappClassLoader
  context: ROOT
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@76ed5528

    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:283)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:554)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:321)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:839)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1091)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:661)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:249)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5087)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1404)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1394)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    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)
Caused by: java.lang.ClassNotFoundException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader:java.net.URLClassLoader@76ed5528;ClassLoader:ParallelWebappClassLoader
  context: ROOT
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@76ed5528

    at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:56)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
    ... 25 more
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
    ... 26 more

May 07, 2019 4:04:12 PM org.apache.naming.NamingContext lookup
WARNING: Unexpected exception resolving reference
java.sql.SQLException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader:java.net.URLClassLoader@76ed5528;ClassLoader:ParallelWebappClassLoader
  context: ROOT
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@76ed5528

    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:283)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:718)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:650)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:468)
    at org.apache.tomcat.jdbc.pool.ConnectionPool.<init>(ConnectionPool.java:143)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118)
    at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.createDataSource(DataSourceFactory.java:554)
    at org.apache.tomcat.jdbc.pool.DataSourceFactory.getObjectInstance(DataSourceFactory.java:241)
    at org.apache.naming.factory.FactoryBase.getObjectInstance(FactoryBase.java:94)
    at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:321)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:839)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:173)
    at org.apache.catalina.core.NamingContextListener.addResource(NamingContextListener.java:1091)
    at org.apache.catalina.core.NamingContextListener.createNamingContext(NamingContextListener.java:661)
    at org.apache.catalina.core.NamingContextListener.lifecycleEvent(NamingContextListener.java:249)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5087)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1404)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1394)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    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)
Caused by: java.lang.ClassNotFoundException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader:java.net.URLClassLoader@76ed5528;ClassLoader:ParallelWebappClassLoader
  context: ROOT
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@76ed5528

    at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:56)
    at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:271)
    ... 25 more
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285)
    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:348)
    at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
    ... 26 more

May 07, 2019 4:04:12 PM org.apache.catalina.core.NamingContextListener addResource
WARNING: Failed to register in JMX: javax.naming.NamingException: Unable to load class: com.mysql.jdbc.Driver from ClassLoader:java.net.URLClassLoader@76ed5528;ClassLoader:ParallelWebappClassLoader
  cont8ext: ROOT
  delegate: false
----------> Parent Classloader:
java.net.URLClassLoader@76ed552

Expected Result : It Must not throw any exception of jar as jar is already present in the /WEB-INF/lib/, as well as in tomcat/lib folder.

Actual Result : It is throwing Exception as stated above.

Answer 1

I encountered this error when working on a Java Project in Debian 10.

The issue was that I had multiple .jar files for MySQL JDBC connector, that is:

mysql-connector-java-5.1.27.jar
mysql-connector-java-5.1.27.jar-1

Here's how I fixed it:

I simply deleted both files starting with the main file:

sudo rm -rf mysql-connector-java-5.1.27.jar
sudo rm -rf mysql-connector-java-5.1.27.jar-1

Then I downloaded a copy of the file into the lib directory of tomcat (/opt/tomcat/lib) again:

sudo wget https://repo1.maven.org/maven2/mysql/mysql-connector-java/5.1.27/mysql-connector-java-5.1.27.jar

And everything worked fine again.

That's all.

I hope this helps

Answer 2

You are apparently trying to load a MySQL JDBC driver class (com.mysql.jdbc.Driver) from an Oracle JDBC JAR file (ojdbc6.jar)

This won't work.

If you are trying to talk to an Oracle database, you need to use the Driver class name for Oracle JDBC.

If you are trying to talk to a MySQL database, you need to use the appropriate JConnector drivers.

---

Based on your comments, the problem is that you put the JDBC driver JAR file in the wrong place. If you are using Tomcat's JNDI Datasource configuration mechanism, the driver JARs need to be in $CATALINA_HOME/lib ... as per the instructions.

This is because the drivers are loaded by core Tomcat code, not by your webapp. Your webapp's WEB-INF/lib directory won't be on the classpath for the classloader for the core.

Answer 3

I want to post an answer after few more brainstorming(atleast in my case).

WEB-INF/lib folder should contains both jars, if in case it is not picked from there by class loader in some strange scenario(my case), copy the same in tomcat/lib folder.

It worked it for me, so posting an answer, I am open for any other views.