Fix for #317 - Interactive/Agent mode NullPointerException (first time user) (#318)

* The bug happens when in streaming mode and the model has been detected as not supporting tools.

* Merged dev and removed unused var in JeddictBrain.pairProgrammer

Author: stefanofornari

src/main/java/io/github/jeddict/ai/lang/JeddictBrain.java

@@ -27,7 +27,6 @@
 import dev.langchain4j.data.message.UserMessage;
 import dev.langchain4j.exception.ToolExecutionException;
 import dev.langchain4j.memory.chat.MessageWindowChatMemory;
-import dev.langchain4j.model.chat.ChatModel;
 import dev.langchain4j.model.chat.listener.ChatModelErrorContext;
 import dev.langchain4j.model.chat.listener.ChatModelListener;
 import dev.langchain4j.model.chat.listener.ChatModelRequestContext;
@@ -207,8 +206,6 @@ public JeddictBrain withMemory(int size) {
      * @return an instance of the configured agent
      */
     public <T> T pairProgrammer(PairProgrammer.Specialist specialist) {
-        ChatModel chatModel = null;
-
         if (specialist == PairProgrammer.Specialist.HACKER) {
             if (!probeToolSupport()) {
                 specialist = PairProgrammer.Specialist.HACKER_WITHOUT_TOOLS;
@@ -234,7 +231,7 @@ public void onResponse(ChatModelResponseContext ctx) {
         if (streaming) {
             builder.streamingChatModel(model(modelListener));
         } else {
-            builder.chatModel(chatModel = model(modelListener));
+            builder.chatModel(model(modelListener));
         }
         if (memorySize > 0) {
             builder.chatMemory(MessageWindowChatMemory.withMaxMessages(memorySize));
@@ -256,7 +253,7 @@ public void onResponse(ChatModelResponseContext ctx) {
         builder.toolArgumentsErrorHandler(this::toolArgumentsErrorHandler);
 
         if (specialist == PairProgrammer.Specialist.HACKER_WITHOUT_TOOLS) {
-            final HackerWithoutTools hacker = new HackerWithoutTools(chatModel, builder, tools);
+            final HackerWithoutTools hacker = new HackerWithoutTools(model(modelListener), builder, tools);
             hacker.maxIterations(25);
 
             return (T) hacker;