Odata JDBC Service: getting NullPointerException: while trying to invoke the method

Question

Hi,
I am testing OData, for that I followed the steps given in this tutorial:
http://scn.sap.com/community/developer-center/mobility-platform/blog/2014/06/10/creating-an-odata-service-based-on-sap-gateway-soap-jdbc-and-jpa-data-sources-ba
It wasn't working as it should, so to understand it better, I created a new project with Stock table only.
Manually entered all it's properties and then deploy it.
Issue1: when I create a JDBC connection to connect with derby database, The driver field has maximum limit and whole driver string is not copied. Attached is the screen shot.
Where as I need to enter: org.apache.derby.jdbc.ClientDriver.
Issue 2: I can't test the connection from here, weather it's working fine or not ?
Issue 3:
When I deploy the project and test the result, I get the Stock Service, But when I try to run this, I get nullpointer exception.
URL: http://localhost:8080/gateway/odata/sap/WSTest1;v=1
Response:
<?xml version="1.0" encoding="utf-8"?>
<service xml:base="http://localhost:8080/gateway/odata/sap/WSTest1;v=1/" xmlns="http://www.w3.org/2007/app" xmlns:atom="http://www.w3.org/2005/Atom">
  <workspace>
   <atom:title>Default</atom:title>
   <collection href="StockSet">
   <atom:title>StockSet</atom:title>
   </collection>
  </workspace>
</service>
Now I need to run StockSet, so next url to access the stock list,
to get stocks:
http://localhost:8080/gateway/odata/sap/WSTest1;v=1/SAP/StockSet
Now I get the following response:
    <?xml version="1.0" ?>
    <error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
    <code>
    </code>
    <message xml:lang="en">java.lang.NullPointerException: while trying to invoke the method java.lang.Object.hashCode() of a null object loaded from local variable 'k'</message>
    </error>
I am not able to figure out, why I am getting this error and how to fix it.
All I want is to create a ODAta on ESPM_STOCK sample table given in example.
Looking forward to hear from you.
Thanks.

Answer 1

Waqas Sadiq
Issue1: when I create a JDBC connection to connect with derby database, The driver field has maximum limit and whole driver string is not copied. Attached is the screen shot.
Are you working on SMP3.0 (lower version than SP03)?
If yes, then there is character restriction in SMP3.0 (SP00, SP01), maximum length for a database driver is 25 characters.
e.g. if driver name is oracle.jdbc.driver.OracleDriver but when you enter this, then you will see onlyoracle.jdbc.driver.Oracle
Until unless we pass the correct driver value things will not work. there is a workaround for this. You create a desitnation with restricted character length.
You would be seeing a property file for each created destination underC:\SAP\MobilePlatform3\Server\config_master\service.destinations\destinations
Go there and open the created "OracleDB" and edit the "DriverName" to the full string:oracle.jdbc.driver.OracleDriver
Please go through this blog for more understanding:
http://scn.sap.com/community/developer-center/mobility-platform/blog/2014/01/09/how-to-connect-an-oracle-db-with-integration-gateway-in-smp3
Note: seems this problem has been resolved in SMP3 SP03
Issue 2: I can't test the connection from here, weather it's working fine or not ?
I didnt find a way to test a destination. So you have to be sure about what all values you are entering.
Once you are done with Destination creation, map it to the respective deployed service under "services" tab.
Issue 3: When I deploy the project and test the result, I get the Stock Service, But when I try to run this, I get nullpointer exception
Make sure you have corrected "Database driver" name manually. And then check if you are facing same issue.
Does this URL expect any input parameters?
http://localhost:8080/gateway/odata/sap/WSTest1;v=1/SAP/StockSet
Regards,
JK