MySQL connections not closing

I have a web application running on Tomcat7 that connects to MySQL 5.5.

I have two servers with the same code:

• Ubuntu

• Red Hat

Ubuntu works fine with 8-16 persistent connections, but Red Hat merges connections and the number of connections grows, never going down. The server eventually drops ~ 152 connections.

The code is called to close the connection:

try {
    conn.close();           
} catch (SQLException e) {
    exceptionController.logException(this.getClass().getSimpleName(), "finalize Db", e.getMessage(), false);
}finally{
    conn = null;
}

      

        
        
        
      

    

All connections to MySQL from this application.

Why is there a difference in behavior? Are there configuration options that I should be aware of - like closing the sleeping connection settings ?

Ubuntu Server Status:

Red Hat server status:

Partial netlist screen:

I found this post that seems to have slowed down o / s connections, but they are still crawling.

EDIT

Research indicates improper closing of connections. Why would connections be closed in one environment but not another?

I edited my.cnf

with the following setting:

wait_timeout=30

      

        
        
        
      

    

However, client connections slept and never die. The server was restarted with a new setting.

What? I do not understand?