Validate the result of concatenation with getRealPath("/")

This rule flags Java code that has references to the following methods and parameters:

• javax.servlet.http.HttpServletRequest.getRealPath("/")
• javax.servlet.ServletContext.getRealPath("/")
• javax.servlet.ServletRequest.getRealPath("/")

In Tomcat, these method calls will return a String ending with a forward slash. In Liberty and traditional WebSphere, the return value will not end with a forward slash. As a result, String concatenation with this method may point to a valid file in Tomcat, but not in WebSphere. For each method call flagged, check that any code using the result accounts for the lack of a trailing slash in WebSphere.

For example, assume that you have installed an exploded war to /path/app.war. Then calling getRealPath("/") has the following results:

• Tomcat: /path/app.war/
• WebSphere: /path/app.war