HTTP Status 500 - com.javachap.service.impl.ServiceException

Hi Folks ,
While going through JDBC module 33 I cam across this error on my setup

[b:3ros25lf]Error[/b:3ros25lf]
HTTP Status 500 - com.javachap.service.impl.ServiceException: org.hibernate.exception.GenericJDBCException: Cannot open connection

[b:3ros25lf]Question - How should I resolve this ?[/b:3ros25lf]

[b:3ros25lf]Data Pointers[/b:3ros25lf]

1.) This error came up after I deployed the application lead app on tomcat.
2.) As soon as I login this error comes.

[b:3ros25lf]Error Details[/b:3ros25lf]

HTTP Status 500 - com.javachap.service.impl.ServiceException: org.hibernate.exception.GenericJDBCException: Cannot open connection

type Exception report

message com.javachap.service.impl.ServiceException: org.hibernate.exception.GenericJDBCException: Cannot open connection

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: com.javachap.service.impl.ServiceException: org.hibernate.exception.GenericJDBCException: Cannot open connection
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:286)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

com.javachap.service.impl.ServiceException: org.hibernate.exception.GenericJDBCException: Cannot open connection
com.javachap.service.impl.UserServiceImpl.authenticate(UserServiceImpl.java:53)
com.javachap.web.controller.LoginAction.execute(LoginAction.java:29)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

org.hibernate.exception.GenericJDBCException: Cannot open connection
org.hibernate.exception.ErrorCodeConverter.handledNonSpecificException(ErrorCodeConverter.java:92)
org.hibernate.exception.ErrorCodeConverter.convert(ErrorCodeConverter.java:80)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
org.hibernate.jdbc.AbstractBatcher.openConnection(AbstractBatcher.java:384)
org.hibernate.jdbc.JDBCContext.connect(JDBCContext.java:141)
org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:88)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:85)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1090)
org.hibernate.loader.Loader.doQuery(Loader.java:362)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:203)
org.hibernate.loader.Loader.doList(Loader.java:1499)
org.hibernate.loader.Loader.list(Loader.java:1482)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:365)
org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:268)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:782)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:74)
com.javachap.service.impl.UserServiceImpl.authenticate(UserServiceImpl.java:47)
com.javachap.web.controller.LoginAction.execute(LoginAction.java:29)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

root cause

java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2851)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:753)
com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:3562)
com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1154)
com.mysql.jdbc.Connection.createNewIO(Connection.java:1702)
com.mysql.jdbc.Connection.<init>(Connection.java:405)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:268)
java.sql.DriverManager.getConnection(DriverManager.java:664)
java.sql.DriverManager.getConnection(DriverManager.java:208)
org.hibernate.connection.DriverManagerConnectionProvider.getConnection(DriverManagerConnectionProvider.java:110)
org.hibernate.jdbc.AbstractBatcher.openConnection(AbstractBatcher.java:381)
org.hibernate.jdbc.JDBCContext.connect(JDBCContext.java:141)
org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:88)
org.hibernate.jdbc.AbstractBatcher.prepareQueryStatement(AbstractBatcher.java:85)
org.hibernate.loader.Loader.prepareQueryStatement(Loader.java:1090)
org.hibernate.loader.Loader.doQuery(Loader.java:362)
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:203)
org.hibernate.loader.Loader.doList(Loader.java:1499)
org.hibernate.loader.Loader.list(Loader.java:1482)
org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:365)
org.hibernate.hql.ast.QueryTranslatorImpl.list(QueryTranslatorImpl.java:268)
org.hibernate.impl.SessionImpl.list(SessionImpl.java:782)
org.hibernate.impl.QueryImpl.list(QueryImpl.java:74)
com.javachap.service.impl.UserServiceImpl.authenticate(UserServiceImpl.java:47)
com.javachap.web.controller.LoginAction.execute(LoginAction.java:29)
org.apache.struts.chain.commands.servlet.ExecuteAction.execute(ExecuteAction.java:58)
org.apache.struts.chain.commands.AbstractExecuteAction.execute(AbstractExecuteAction.java:67)
org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:304)
org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:190)
org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:462)
javax.servlet.http.HttpServlet.service(HttpServlet.java:648)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

note The full stack trace of the root cause is available in the Apache Tomcat/8.0.27 logs.
Apache Tomcat/8.0.27