java.lang.Object.wait(Native Method)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)

package cn.listener;

import java.sql.Driver;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Enumeration;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
import javax.servlet.annotation.WebListener;

import com.mysql.jdbc.AbandonedConnectionCleanupThread;


@WebListener
public class ContextFinalizer implements ServletContextListener {

  public void contextInitialized(ServletContextEvent sce) {
  }

  public void contextDestroyed(ServletContextEvent sce) {
    Enumeration<Driver> drivers = DriverManager.getDrivers();
    Driver d = null;
    while (drivers.hasMoreElements()) {
      try {
        d = drivers.nextElement();
        DriverManager.deregisterDriver(d);
        System.out.println(String.format("ContextFinalizer:Driver %s deregistered", d));
      } catch (SQLException ex) {
        System.out.println(String.format("ContextFinalizer:Error deregistering driver %s", d) + ":" + ex);
      }
    }
    try {
      AbandonedConnectionCleanupThread.shutdown();
    } catch (InterruptedException e) {
      System.out.println("ContextFinalizer:SEVERE problem cleaning up: " + e.getMessage());
      e.printStackTrace();
    }
  }
}

 <listener>
  <listener-class>cn.listener.ContextFinalizer</listener-class>
 </listener>