Summary
Debugging and troubleshooting in Application Express can be challenging because of different technologies used in Application Express. Each technology has its own set of tools for effective troubleshooting and debugging.
Fortunately, there is a variety of readily available options for debugging APEX applications. The key is to know how APEX generates pages, to know the tenets of the application, and to employ a variety of tactics to meet the challenge at hand.
Running the pages of the application in debug mode shows exactly which steps are taken. Use Oracle SQL Developer to not only debug your PL/SQL database code, but also to remotely debug the PL/SQL called from the APEX application.
There are numerous utility reports available that can assist you in the troubleshooting process. The Advisor can advise you before the trouble begins.
Specific web development tools, such as Web Developer, Firebug, and console wrapper, can assist with checking the HTML, CSS, and JavaScript code.