title: JDBC: Oracle Application Server and "The Network Adapter could not establish the connection" error
body: <p>I am getting the error: "The Network Adapter could not establish the connection" from a web application deployed in Oracle Application Server 10g.  The database is local, so there shouldn't be any connection issues.</p>
  
  <p>First test: I can connect to the DB no problem from SQL plus, run queries, etc.
  Second test: I can connect to the database no problem from a locally installed JDeveloper on the server, and run queries, etc. no problem.  This works with the short JDBC scring, and the long one (shown below).</p>
  
  <p>jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=abcd)(SERVER=DEDICATED)))</p>
  
  <p>Yet when I run the web app, it gives the above error.  It seems too generic for me to do anything about.  </p>
  
  <p>Any suggestions on how to solve this?  I assume that Oracle logs failed connection attempts somewhere, but I couldn't find anything relevant in the databases alert.log file.</p>
  
  <p>It is possible that the problem is that the application is using an old jsdk, but I would assume that then some version mismatch error would be given instead of a "network connection" message.</p>
  
  <p>Edit: I don't know whether this is an OAS problem or a problem with the specific Web Application, I would like to figure this out first, as it seems it should be easy.  In WebSphere, there is a "test connection" button to dest data-sources you have added, but it seems there is no such functionality in OAS10?  Somehow I think there must be, and I am just missing it because I am not an OAS expert.</p>
  
  <p>Edit 2: I installed JDevelop on a remote machine and connected to the database with no problems, so I know for sure it isn't an issue with the database connectivity itself - it seems like it must be a problem within OAS?</p>