Fix PMD

Author: a-d

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiChatCompletionRequest.java

@@ -306,13 +306,13 @@ CreateChatCompletionRequest createCreateChatCompletionRequest() {
       toolsCombined.addAll(this.tools);
     }
     if (this.toolsExecutable != null) {
-      for (OpenAiTool tool : this.toolsExecutable) {
+      for (final OpenAiTool tool : this.toolsExecutable) {
         toolsCombined.add(tool.createChatCompletionTool());
       }
     }
 
     final var request = new CreateChatCompletionRequest();
-    for (OpenAiMessage message : this.messages) {
+    for (final OpenAiMessage message : this.messages) {
       request.addMessagesItem(OpenAiUtils.createChatCompletionRequestMessage(message));
     }
     if (this.stop != null) {

foundation-models/openai/src/main/java/com/sap/ai/sdk/foundationmodels/openai/OpenAiChatCompletionResponse.java

@@ -109,7 +109,9 @@ public OpenAiAssistantMessage getMessage() {
    * @return the list of tool messages that were serialized for the computed results. Empty list if
    *     no tools were called.
    */
+  @Nonnull
   public List<OpenAiToolMessage> executeTools() {
-    return OpenAiTool.execute(originalRequest.getToolsExecutable(), getMessage());
+    final var tools = originalRequest.getToolsExecutable();
+    return OpenAiTool.execute(tools != null ? tools : List.of(), getMessage());
   }
 }