Uses lambda

Co-authored-by: Copilot <[email protected]>

Author: lukaszlenart

core/src/main/java/org/apache/struts2/dispatcher/multipart/JakartaStreamMultiPartRequest.java

@@ -136,7 +136,7 @@ protected void processFileItemAsFormField(FileItemInput fileItemInput) throws IO
             return;
         }
 
-        List<String> values = parameters.computeIfAbsent(fieldName, k -> new ArrayList<>());
+        List<String> values = parameters.computeIfAbsent(fieldName, ArrayList::new);
         values.add(fieldValue);
     }