Get BaseResourceException with JDBC ds.getConnection()

Question

Hi,
I have created a stateless sessionbean with the intension to connect to the default SAP database by JDBC. Therefore I have created 3 project: a dictionairy project, a enterprise java bean project and a j2ee application project. Within the j2ee application project I have created a datasource alias:
?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE data-source-aliases SYSTEM "data-source-aliases.dtd">
<data-source-aliases>
     <aliases>
          <data-source-name>${com.sap.datasource.default}</data-source-name>
          <alias>UNIQEMA_CONTACT_US</alias>
     </aliases>
</data-source-aliases>
And in the ejb module project I have created also a reference to the datasource:
               <resource-ref>
                    <res-ref-name>UNIQEMA_CONTACT_US</res-ref-name>
                    <res-type>javax.sql.DataSource</res-type>
                    <res-auth>Application</res-auth>
                    <res-sharing-scope>Shareable</res-sharing-scope>
               </resource-ref>
I have also created the following create method in the ejb :
     public void ejbCreate() throws CreateException {
          try {
//               Class.forName("com.sap.dbtech.jdbc.DriverSapDB");
               Context ctx = new InitialContext();
               DataSource ds = (DataSource) ctx.lookup("java:comp/env/UNIQEMA_CONTACT_US");
               conn = ds.getConnection();
          } catch (Exception e) {
               throw new CreateException("e.getMessage");
But when the ejb excutes the ds.getConnection() I got the following error:
com.sap.engine.services.connector.exceptions.BaseResourceException: Cannot get connection. Reason: the thread of component "ejbContexts/sap.com/com.atosorigin.uniqema.contactus.appl/uniqema_contact_us_country" in application "sap.com/com.atosorigin.uniqema.contactus.appl" is currently associated with a restricted resource set and it is not allowed to get connection within it.
Please can someone say what I have done wrong a which feature I have forgotten to set.
regards,
Sander Valkenburg

Answer 1

Hi Sander,
another note on using DS connections:
1. connection as you may know are scarce resources, meant to be shared among apps. Storing a connection in a instance variable of a bean is not a good idea for another reason to: the database times out connections too!
2. proper usage would be something like this
Connection conn = null;
try {
  // acquire conn.
  conn = ds.getConnection();
  // do something with it
} catch( ..) {
} finally {
  // give conn back to pool
  try { if () conn.close(); } catch(Exception e) {}
Regards
Gregor