Share a solution that uses c3p0,tomcat to escape memory

Http://stackoverflow.com/questions/3320400/to-prevent-a-memory-leak-the-jdbc-driver-has-been-forcibly-unregistered
/**   *  @author  aray chou   *         email:  aray (dot) Chou (dot) CN (at) gmail (dot) com   *          replace  "(dot)"  with  "."  and replace  "(at)"  with  "@"   * * import  javax.servlet.ServletContextEvent; import  Javax.servlet.ServletContextListener; import  Javax.servlet.annotation.WebListener; import  Javax.sql.DataSource;   import  com.mchange.v2.c3p0.DataSources;  /**   *&NBSP;C3P0 Connection pool When the context is shut down (Tomcat server or reload context is turned off), resources are not reclaimed, resulting in memory leaks. Tomcat reported the following error:   * <br />severe: the web application [/xxx] appears  to have started a thread named [ com.mchange.v2.async.threadpoolasynchronousrunner$poolthread-#1] but has failed to  Stop it. this is very likely&nbSp;to create a memory leak.   *    *  This class releases the C3P0 connection pool at the time the context is closed to resolve this type of save and leak problem.   *    *  In addition, the JDBC driver package (for example, Ojdbc6.jar) is placed under $tomcat_home/lib and not in web-inf/lib to address the problem of the JDBC driver causing memory leaks. At this time Tomcat reported the following error:   * severe: a web application registered the jbdc  Driver [oracle.jdbc.oracledriver] but failed to unregister it when the  web application was stopped. to prevent a memory leak, the  jdbc driver has been forcibly unregistered.   * @WebListener () public  class  dbcloser  implements  servletcontextlistener {