Summary: I set up my laptop as a development system to work on a JSP application which connects to an Oracle 10g database. I had installed Oracle locally on my laptop a few times and finally got a stable version up and running, although I still run into issues here and there. One of the problems I was experiencing recently was being unable to open the administration page for a local database I created. It was only happening intermittently and seemed to be related to having multiple network interfaces enabled. If I disabled all of the interfaces I wasn’t using, and left only the one I needed, then it would usually work. However, this poses a problem when I must have more than one interface enabled, such as when connected to another network via a VPN. After much research, I found quite a bit of information about this problem. Seems it is rather common.
Resolution: Most times, the fix for the problem is to install and configure the Microsoft Loopback Adapter. Also, the local hosts file may need to be modified. Details on how to do this can be found easily on the web by doing a quick search for “installing microsoft loopback adapter”. Also, if you throw an “oracle” in the search somewhere, you’ll find a lot of info related to this specific issue. Here’s someone else who was experiencing a similar problem. http://oracleplz.blogspot.com/2006/02/10g-installation-on-windows.html
You may need to verify that the admin port is listening as well. You can test this by running telnet from the command line. For instance, telnet computername 5500. If the connection fails, run a netstat -a command and make sure that the computer is listening on the specfied port. If the system is not listening on the port, then the service is probably not started. To manually start the database service, open up the service list in Windows and make sure that the OracleDBConsole service is started. If it’s unable to start, you may need to manually restart the OracleService service.
Summary: I ran into an issue recently when I was setting up a new computer as a development system. I was using Netbeans as my IDE. In order to develop and test JSP applications, I needed to install Tomcat. Once I had everything installed and configured, I built and ran an application that I knew worked because it was running fine on a different computer. Same configuration, same source code but was unable to run it on the new computer. The issue was that I was receiving an HTTP 500 – Internal Server Error when attempting to access any web pages on the computer using http://localhost as the URL. The first thing I should have tried was attempt to access the application using http://127.0.0.1/ instead of http://localhost/. But instead, I proceeded to uninstall and re-install everything! Including all of the Java components. When this didn’t work, I tried installing the Sun Java Application Server thinking there might be something wrong with Tomcat. This didn’t work either. I checked the local hosts file and didn’t see anything out of the norm. After fighting with this issue for a few days, I finally figured out what the problem was and how to fix it, but till this day could not tell you why the problem exists.
Resolution: After comparing all of the configuration options on the computer that worked with the one that didn’t, I noticed that the only difference was that the new computer’s browser was configured to use a proxy server. When I removed the proxy configuration from the browser settings, I was then able to access all locally hosted applications using the http://localhost/ URL as well as the http://127.0.0.1/ URL. Who knows why….
