1. A method comprising, by one or more computer systems: accessing one or more JAVASERVER PAGES (JSP) files, one or more Extensible Markup Language (XML) configuration files, and one or more class files of an event-driven application; parsing the JSP files, wherein parsing the JSP files comprises extracting data from the JSP files that encode user or server events supported by the event-driven application; parsing the XML configuration files, wherein parsing the XML configuration files comprises extracting data from the XML configuration files that encode definitions used by the event-driven application when deployed; parsing the class files, wherein parsing the class files comprises extracting data from the class files that encode one or more actions or one or more forms used by the event-driven application when deployed; storing the extracted data as an abstract syntax tree (AST); populating a page transition graph (PTG) of the event-driven application based on the AST; and checking the PTG for navigation errors in the event-driven application.