SEVERE: Unable to create initial connections of pool - tomcat 7 with context.xml file

Question

I tried to run project on tomcat 7.0.52 and initialize to DB through context.xml file.

But it throws bunch of exceptions, I couldn\'t figur

Answer 1

I have also dealt with this exception after a fully working context.xml setup was adjusted. I didn't want environment details in the context.xml, so I took them out and saw this error. I realized I must fully create this datasource resource in code based on System Property JVM -D args.

Original error with just user/pwd/host removed: org.apache.tomcat.jdbc.pool.ConnectionPool init SEVERE: Unable to create initial connections of pool.

Removed entire contents of context.xml and try this: Initialize on startup of app server the datasource object sometime before using first connection. If using Spring this is good to do in an @Configuration bean in @Bean Datasource constructor.

package to use: org.apache.tomcat.jdbc.pool.*

PoolProperties p = new PoolProperties();
p.setUrl(jdbcUrl);
            p.setDriverClassName(driverClass);
            p.setUsername(user);
            p.setPassword(pwd);
            p.setJmxEnabled(true);
            p.setTestWhileIdle(false);
            p.setTestOnBorrow(true);
            p.setValidationQuery("SELECT 1");
            p.setTestOnReturn(false);
            p.setValidationInterval(30000);
            p.setValidationQueryTimeout(100);
            p.setTimeBetweenEvictionRunsMillis(30000);
            p.setMaxActive(100);
            p.setInitialSize(5);
            p.setMaxWait(10000);
            p.setRemoveAbandonedTimeout(60);
            p.setMinEvictableIdleTimeMillis(30000);
            p.setMinIdle(5);
            p.setLogAbandoned(true);
            p.setRemoveAbandoned(true);
            p.setJdbcInterceptors(
              "org.apache.tomcat.jdbc.pool.interceptor.ConnectionState;"+
              "org.apache.tomcat.jdbc.pool.interceptor.StatementFinalizer");
            org.apache.tomcat.jdbc.pool.DataSource ds = new org.apache.tomcat.jdbc.pool.DataSource();
            ds.setPoolProperties(p);
            return ds;

Answer 2

I use sprint-boot (2.1.1), and mysql version is 8.0.13. I add dependency in pom, solve my problem.

 <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.13</version>
 </dependency>

MySQL Connector/J » 8.0.13 link: https://mvnrepository.com/artifact/mysql/mysql-connector-java/8.0.13
MySQL Connector/J » All the version link: https://mvnrepository.com/artifact/mysql/mysql-connector-java

Answer 3

You have to add a MySQL jdbc driver to the classpath.

Either put a MySQL binary jar to tomcat lib folder or add it to we application WEB-INF/lib folder.

You can find binary jar (Change version accordingly): https://mvnrepository.com/artifact/mysql/mysql-connector-java/5.1.27

Answer 4

When you encounter exceptions like this, the most useful information is generally at the bottom of the stacktrace:

Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
  at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
  ...
  at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:246)

The problem is that Tomcat can't find com.mysql.jdbc.Driver. This is usually caused by the JAR containing the MySQL driver not being where Tomcat expects to find it (namely in the webapps/<yourwebapp>/WEB-INF/lib directory).