NullPointerException « Connection « Java Database Q&A

1. java.lang.NullPointerException - ResultSet

I am getting the following error:

    at oracle.jdbc.driver.ScrollableResultSet.cacheRowAt(
    at oracle.jdbc.driver.ScrollableResultSet.isValidRow(
    at website.web.InboxReader.getkeywordImportance(
    at website.web.InboxReader.main(
There ...

3. Simple JDBC problem - Connection throws Nullpointerexception

package bean; import java.util.ArrayList; import java.sql.*; import javax.naming.*; import javax.sql.*; public class db{ private Connection conn; public db(){ try{ Context initCtx = new InitialContext(); Context envCtx = (Context) initCtx.lookup("java:comp/env"); DataSource ds = (DataSource)envCtx.lookup("jdbc/db"); Connection conn = ds.getConnection(); } catch(SQLException e){ } catch(NamingException e){ } } public void close(){ try{ conn.close(); } catch(SQLException e){ } } public boolean loginUser(String uName, String uPwd){ ...

4. DB connection and a null pointer exception

Hey everyone, If you guys don't mind reading some code i need some suggestions as to why i am receiving a NullPointer Exception. Tomcat says it encountered an internal error. Ive narrowed the problem down to line 41, in the DataAccess class. I don't understand why this is giving me a problem because ive use this code before in a java ...

6. Database Connection Pooling java.lang.NullPointerException. Help please

Dear Pros and Noobs I am stuck with the Database Connection Pooling problem. I have created and tested a Database Pooling successfully. But recently I have faced a problem saying java.lang.NullPointerException malo.controller.ProfileController.processRequest( malo.controller.ProfileController.doGet( javax.servlet.http.HttpServlet.service( javax.servlet.http.HttpServlet.service( org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter( Could anyone help me to solve the problem please. Before I post this, I have tried to find the answer in the Internet and ...

7. Null pointer exception when connecting to database

In the try catch block where you create the connection, you are catching ClassNotFoundException, and the SQLException, but then your method still continues. So, in the next block, where you try to use the connection, it's null because there was an exception in the previous block. Don't simply "log" an exception and continue (as you do for ClassNotFoundException) when the raising ...

8. nullpointerexception when connecting to database

I generally recommend checking a connection to any external resource to make sure that it's active before trying to use it, but whether you test it or you catch the exception your underlying problem is that your connection object is not fully instantiated when you try to call a method on it. Boom! NullPointerException. Just my 2 krupplenicks on the subject, ...