Cannot create JDBC driver of class for connect URL null I do not understand this exception

Question

Why does it say null URL and gives a empty     class in the exception when I have provided the database URL  I am trying to connect to a derby database via a servlet while using Tomcat  When the servlet gets run  I get the following exceptions  org apache tomcat dbcp dbcp SQLNestedException  Cannot create JDBC driver of class    for connect URL  null   at org apache tomcat dbcp dbcp BasicDataSource createConnectionFactory BasicDataSource java 1452  at org apache tomcat dbcp dbcp BasicDataSource createDataSource BasicDataSource java 1371  at org apache tomcat dbcp dbcp BasicDataSource getConnection BasicDataSource java 1044   at servlets servlet 1 doGet servlet 1 java 23     --- gt  Marked the statement in servlet  at javax servlet http HttpServlet service HttpServlet java 621  at javax servlet http HttpServlet service HttpServlet java 722  at org apache catalina core ApplicationFilterChain internalDoFilter ApplicationFilterChain java 304  at org apache catalina core ApplicationFilterChain doFilter ApplicationFilterChain java 210  at org netbeans modules web monitor server MonitorFilter doFilter MonitorFilter java 393  at org apache catalina core ApplicationFilterChain internalDoFilter ApplicationFilterChain java 243  at org apache catalina core ApplicationFilterChain doFilter ApplicationFilterChain java 210  at org apache catalina core StandardWrapperValve invoke StandardWrapperValve java 224  at org apache catalina core StandardContextValve invoke StandardContextValve java 169  at org apache catalina authenticator AuthenticatorBase invoke AuthenticatorBase java 472  at org apache catalina core StandardHostValve invoke StandardHostValve java 168  at org apache catalina valves ErrorReportValve invoke ErrorReportValve java 100  at org apache catalina valves AccessLogValve invoke AccessLogValve java 929  at org apache catalina core StandardEngineValve invoke StandardEngineValve java 118  at org apache catalina connector CoyoteAdapter service CoyoteAdapter java 405  at org apache coyote http11 AbstractHttp11Processor process AbstractHttp11Processor java 964  at org apache coyote AbstractProtocol AbstractConnectionHandler process AbstractProtocol java 515  at org apache tomcat util net JIoEndpoint SocketProcessor run JIoEndpoint java 302  at java util concurrent ThreadPoolExecutor Worker runTask ThreadPoolExecutor java 885  at java util concurrent ThreadPoolExecutor Worker run ThreadPoolExecutor java 907  at java lang Thread run Thread java 619  Caused by  java lang NullPointerException at sun jdbc odbc JdbcOdbcDriver getProtocol JdbcOdbcDriver java 507  at sun jdbc odbc JdbcOdbcDriver knownURL JdbcOdbcDriver java 476  at sun jdbc odbc JdbcOdbcDriver acceptsURL JdbcOdbcDriver java 307  at java sql DriverManager getDriver DriverManager java 253  at org apache tomcat dbcp dbcp BasicDataSource createConnectionFactory BasicDataSource java 1437      24 more  Servlet   package servlets   import java io IOException  import java sql Connection  import java sql PreparedStatement  import java sql ResultSet  import javax naming Context  import javax naming InitialContext  import javax servlet http    import javax servlet    import javax sql DataSource   public class servlet 1 extends HttpServlet         Override      public void doGet HttpServletRequest request  HttpServletResponse response  throws ServletException  IOException           try                 String queryString   request getQueryString                System out println  quot                     quot                Context initContext   new InitialContext                Context envContext    Context initContext lookup  quot java comp env quot                DataSource ds    DataSource envContext lookup  quot jdbc PollDatasource quot                Connection connection   ds getConnection       -- gt LINE 23             String sqlQuery    quot select   from PollResult quot               PreparedStatement statement   connection prepareStatement sqlQuery               ResultSet set   statement executeQuery                System out println  quot after the final statement quot              catch  Exception exc                exc printStackTrace                       What exception is this  Why do I get this exception  I have added the following tag in context xml of Tomcat    lt Resource name  quot jdbc PollDatasource quot  auth  quot Container quot  type  quot javax sql DataSource quot  driverClassName  quot org apache derby jdbc EmbeddedDriver quot  url  quot jdbc derby   localhost 1527 poll database create true quot  username  quot suhail quot  password  quot suhail quot  maxActive  quot 20 quot  maxIdle  quot 10 quot  maxWait  quot -1 quot    gt   and this in web xml    lt resource-ref gt     lt description gt my connection lt  description gt     lt res-ref-name gt jdbc PollDatasource lt  res-ref-name gt     lt res-type gt javax sql DataSource lt  res-type gt     lt res-auth gt Container lt  res-auth gt   lt  resource-ref gt   Where am I making a mistake  Image that shows the database URL    NOTE   After the answer by  Bryan Pendleton I changed the driver to org apache derby jdbc ClientDriver but I get the same exception

User · Answer

The problem could also come because of a lack of SQL driver in your Tomcat installation directory.

I had to had mysql-connector-java-5.1.23-bin.jar in apache-tomcat-9.0.12/lib/ folder.

https://dev.mysql.com/downloads/connector/j/

User · Answer

Context envContext    Context initContext lookup  java comp env      not Context envContext    Context initContext lookup  java  comp env

User · Answer

Several fixes    Use the right driver class name for your environment  if you are using an out-of-process Derby server  then you want ClientDriver  and need to use derbyclient jar   the hostname and port  etc  If you want an in-process Derby server  then you want derby jar  EmbeddedDriver  and a URL that is appropriate for an embedded database  Put your driver JAR file only in Tomcat s lib  directory  Don t put anything in Tomcat s conf context xml  there s really no reason for it  Instead  use your webapp s META-INF context xml to define your  lt Resource gt     The error  Cannot create JDBC driver of class    for connect URL  null  usually occurs because the JDBC driver is not in the right place  or in too many places  like Tomcat s lib  directory but also in the webapp s WEB-INF lib  directory   Please verify that you have the right driver JAR file in the right place

User · Answer

I can t see anything obviously wrong  but perhaps a different approach might help you debug it   You could try specify your datasource in the per-application-context instead of the global tomcat one   You can do this by creating a src main webapp META-INF context xml  I m assuming you re using the standard maven directory structure - if not  then the META-INF folder should be a sibling of your WEB-INF directory   The contents of the META-INF context xml file would look something like    lt  xml version  1 0  encoding  UTF-8   gt    lt Context  optional other attributes as required  gt    lt Resource name  jdbc PollDatasource  auth  Container            type  javax sql DataSource  driverClassName  org apache derby jdbc ClientDriver            url  jdbc derby   localhost 1527 poll database create true            username  suhail  password  suhail  maxActive  20  maxIdle  10  maxWait  -1   gt   lt  Context gt    Obviously the path and docBase would need to match your application s specific details   Using this approach  you don t have to specify the datasource details in Tomcat s context xml file  Although  if you have multiple applications talking to the same database  then your approach makes more sense   At any rate  give this a whirl and see if it makes any difference  It might give us a clue as to what is going wrong with your approach

User · Answer

Did you try to specify resource only in context xml    lt Resource name  jdbc PollDatasource  auth  Container  type  javax sql DataSource  driverClassName  org apache derby jdbc EmbeddedDriver  url  jdbc derby   localhost 1527 poll database create true  username  suhail  password  suhail  maxActive  20  maxIdle  10  maxWait  -1    gt    and remove  lt resource-ref gt  section from web xml   In one project I ve seen configuration without  lt resource-ref gt  section in web xml and it worked   It s an educated guess  but I think  lt resource-ref gt  declaration of JNDI resource named jdbc PollDatasource in web xml may override declaration of resource with same name in context xml and the declaration in web xml is missing both driverClassName and url hence the NPEs for that properties

User · Answer

These two things don t match   driverClassName  org apache derby jdbc EmbeddedDriver  url  jdbc derby   localhost 1527 poll database create true    If you are using the EmbeddedDriver  your URL should not contain network syntax   Conversely  if you are using network syntax  you need to use the ClientDriver   http   db apache org derby docs 10 8 getstart rgsquck35368 html

User · Answer

I was getting this problem because I put context xml into the wrong path     src main resources META-INF context xml   The correct path was     src main webapp META-INF context xml

User · Answer

If you re using an embedded driver  the connectString is just   jdbc derby databaseName     whith options like create true user xxx etc    If you re using client driver  the connect string can be left as is  but if changing the driver gives no result    excuse the question  but are you 100  sure you have started the Derby Network Server as per the Derby Tutorial

User · Answer

I had a similar problem using Tomcat against Oracle  I DID have the context xml in the META-INF directory  on the disc  This file was not showing in the eclipse project though  A simple hit on the F5 refresh and the context xml file appeared and eclipse published it  Everything worked past that  Hope this helps someone   Try hitting F5 in eclipse

User · Answer

If you are using eclipse  you should modify the context xml  from the server project created in your eclipse package explorer  When using tomcat in eclipse it is the only one valid  the others are ignored or overwriten

User · Answer

In my case I solved the problem editing  tomcat  Catalina localhost  mywebapp name  xml  instead of  META-INF context xml

[java] Cannot create JDBC driver of class ' ' for connect URL 'null' : I do not understand this exception

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