<pre style="white-space: pre-wrap; font-family: inherit; margin:0;" id="yMail_cursorElementTracker_1552832014765">I repost my question that I post on StackOverflow here in case anyone can answer it. This is my question about implementation </pre><pre style="white-space: pre-wrap; font-family: inherit; margin:0;" id="yMail_cursorElementTracker_1552832060161">of interface through delegation. Parent class is concrete class which implement an interface through delegation but descendant of this class is not considered as concrete class of the interface.</pre><pre style="white-space: pre-wrap; font-family: inherit; margin:0;" id="yMail_cursorElementTracker_1552832087967"><br></pre><pre style="white-space: pre-wrap; font-family: inherit; margin:0;" id="yMail_cursorElementTracker_1552832459602">Detail of question can be read here</pre><pre style="white-space: pre-wrap; font-family: inherit; margin:0;" id="yMail_cursorElementTracker_1552832495215"><br></pre><pre style="white-space: pre-wrap; font-family: inherit; margin:0;"><a id="linkAnchor_1552831990729" class="linkEnhancr_shared_link" href="https://stackoverflow.com/q/55160258/5855039" data-yahoo-extracted-link="true">https://stackoverflow.com/q/55160258/5855039</a></pre><br><div id="ymail_android_signature">Zamrony P. Juhara</div><div id="yMail_cursorElementTracker_1552832374442"><br></div><div id="yMail_cursorElementTracker_1552832437426"><div style="overflow-wrap: break-word; font-family: sans-serif;">Fano Framework, web application framework for modern Pascal programming language <a rel="nofollow" target="_blank" href="https://fanoframework.github.io" class="yiv5996823291" style="overflow-wrap: break-word; word-break: break-word;">https://fanoframework.github.io</a></div><div id="yMail_cursorElementTracker_1552832440171"><br></div></div><div id="yMail_cursorElementTracker_1552832375266"><br></div>