[WICKET-6092] MockHttpServletResponse causes AbstractMethodError during unit tests

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Won't Fix
• Affects Version/s: 6.21.0
• Component/s: wicket
• Assignee: Martin Tzvetanov Grigorov
• Reporter: Jeremy Sss
• Created: 05/Feb/16 20:55
• Updated: 05/Feb/16 21:59
• Resolved: 05/Feb/16 21:59

Description

As early as Wicket 6.x the Wicket documentation has specified that it supports Java's Servlet API v2.5 or newer (https://wicket.apache.org/start/wicket-6.x.html#servlet-api). Java's Servlet API v3.x specifies that classes who implement the HttpServletResponse interface must implement the getHeaderNames() method which returns the type Collection<String> (http://docs.oracle.com/javaee/7/api/javax/servlet/http/HttpServletResponseWrapper.html#getHeaderNames--). While preforming unit tests using WicketTester, Wicket helpfully uses the MockHttpServletResponse class which defines a getHeaderNames() method that returns type Set<String> (https://ci.apache.org/projects/wicket/apidocs/7.x/org/apache/wicket/protocol/http/mock/MockHttpServletResponse.html#getHeaderNames()).

While running unit tests for code that makes use of the getHeaderNames() method, an AbstractMethodError is thrown due to the incorrect method signature. Wicket's MockHttpServletResponse should implement and override the getHeaderNames() method with the same signature as defined in HttpServletResponse.