Index: /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java
===================================================================
--- /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java	(revision 31849)
+++ /applications/editors/josm/plugins/wikipedia/src/org/wikipedia/WikipediaApp.java	(revision 31850)
@@ -17,4 +17,5 @@
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Scanner;
 import java.util.regex.Matcher;
@@ -247,11 +248,12 @@
             if (this == o) return true;
             if (o == null || getClass() != o.getClass()) return false;
-
-            WikipediaLangArticle that = (WikipediaLangArticle) o;
-
-            if (article != null ? !article.equals(that.article) : that.article != null) return false;
-            if (lang != null ? !lang.equals(that.lang) : that.lang != null) return false;
-
-            return true;
+            final WikipediaLangArticle that = (WikipediaLangArticle) o;
+            return Objects.equals(lang, that.lang) &&
+                    Objects.equals(article, that.article);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(lang, article);
         }
     }