fix(java-spring-ai-agents): supplementary KB RAG prompt + sync demo-scripts to RC2

- ChatService: use a custom QuestionAnswerAdvisor promptTemplate so KB docs are
  treated as supplementary reference material (agent still answers from its own
  knowledge when policies don't cover the question)
- demo-scripts/03-kb.sh: add spring-boot-starter-validation, supplementary KB
  template, drop dead null-check
- demo-scripts/04-tools.sh: drop dead bean null-checks
- demo-scripts/01-create.sh: bootVersion 4.0.6 (Initializr resolves Spring AI RC2)

Author: Yuriy Bezsonov

apps/java-spring-ai-agents/aiagent/src/main/java/com/example/agent/ChatService.java

@@ -14,6 +14,7 @@
 import org.springframework.ai.chat.client.advisor.vectorstore.QuestionAnswerAdvisor;
 import org.springframework.ai.chat.memory.ChatMemory;
 import org.springframework.ai.chat.model.ChatModel;
+import org.springframework.ai.chat.prompt.PromptTemplate;
 import org.springframework.ai.model.tool.ToolCallingChatOptions;
 import org.springframework.ai.tool.ToolCallbackProvider;
 import org.springframework.ai.vectorstore.VectorStore;
@@ -75,7 +76,14 @@ public ChatService(AgentCoreMemory agentCoreMemory,
         logger.info("Memory enabled: {} advisors", agentCoreMemory.advisors.size());
 
         // Knowledge Base (RAG)
-        advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore).build());
+        advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore)
+            .promptTemplate(PromptTemplate.builder().template("""
+                {query}
+
+                The following documents may be relevant as reference material:
+                {question_answer_context}
+                """).build())
+            .build());
         logger.info("KB RAG enabled");
 
         // ContextAdvisor

apps/java-spring-ai-agents/demo-scripts/01-create.sh

@@ -16,7 +16,7 @@ else
       -d language=java \
       -d packaging=jar \
       -d javaVersion=25 \
-      -d bootVersion=4.0.2 \
+      -d bootVersion=4.0.6 \
       -d baseDir=aiagent \
       -d groupId=com.example \
       -d artifactId=agent \

apps/java-spring-ai-agents/demo-scripts/03-kb.sh

@@ -21,7 +21,7 @@ fi
 if ! grep -q "spring-ai-starter-vector-store-bedrock-knowledgebase" pom.xml; then
     sed -i '/<artifactId>spring-ai-agentcore-memory<\/artifactId>/,/<\/dependency>/{
         /<\/dependency>/a \
-\t\t<!-- Knowledge Base (RAG) -->\n\t\t<dependency>\n\t\t\t<groupId>org.springframework.ai</groupId>\n\t\t\t<artifactId>spring-ai-starter-vector-store-bedrock-knowledgebase</artifactId>\n\t\t</dependency>\n\t\t<dependency>\n\t\t\t<groupId>org.springframework.ai</groupId>\n\t\t\t<artifactId>spring-ai-vector-store-advisor</artifactId>\n\t\t</dependency>
+\t\t<!-- Knowledge Base (RAG) -->\n\t\t<dependency>\n\t\t\t<groupId>org.springframework.ai</groupId>\n\t\t\t<artifactId>spring-ai-starter-vector-store-bedrock-knowledgebase</artifactId>\n\t\t</dependency>\n\t\t<dependency>\n\t\t\t<groupId>org.springframework.ai</groupId>\n\t\t\t<artifactId>spring-ai-vector-store-advisor</artifactId>\n\t\t</dependency>\n\t\t<!-- Bean Validation (Hibernate Validator) - required by the Knowledge Base configuration properties -->\n\t\t<dependency>\n\t\t\t<groupId>org.springframework.boot</groupId>\n\t\t\t<artifactId>spring-boot-starter-validation</artifactId>\n\t\t</dependency>
     }' pom.xml
 fi
 
@@ -83,17 +83,15 @@ public class ChatService {
         logger.info("Memory enabled: {} advisors", agentCoreMemory.advisors.size());
 
         // Knowledge Base (RAG)
-        if (kbVectorStore != null) {
-            advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore)
-                .promptTemplate(PromptTemplate.builder().template("""
-                    {query}
-
-                    The following documents may be relevant as reference material:
-                    {question_answer_context}
-                    """).build())
-                .build());
-            logger.info("KB RAG enabled");
-        }
+        advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore)
+            .promptTemplate(PromptTemplate.builder().template("""
+                {query}
+
+                The following documents may be relevant as reference material:
+                {question_answer_context}
+                """).build())
+            .build());
+        logger.info("KB RAG enabled");
 
         this.chatClient = chatClientBuilder
             .defaultSystem(SYSTEM_PROMPT)

apps/java-spring-ai-agents/demo-scripts/04-tools.sh

@@ -222,28 +222,24 @@ public class ChatService {
         logger.info("Memory enabled: {} advisors", agentCoreMemory.advisors.size());
 
         // Knowledge Base (RAG)
-        if (kbVectorStore != null) {
-            advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore)
-                .promptTemplate(PromptTemplate.builder().template("""
-                    {query}
-
-                    The following documents may be relevant as reference material:
-                    {question_answer_context}
-                    """).build())
-                .build());
-            logger.info("KB RAG enabled");
-        }
+        advisors.add(QuestionAnswerAdvisor.builder(kbVectorStore)
+            .promptTemplate(PromptTemplate.builder().template("""
+                {query}
+
+                The following documents may be relevant as reference material:
+                {question_answer_context}
+                """).build())
+            .build());
+        logger.info("KB RAG enabled");
 
         // ContextAdvisor
         advisors.add(contextAdvisor);
         logger.info("Context Advisor enabled");
 
         // Tools
         List<Object> localTools = new ArrayList<>();
-        if (webGroundingTools != null) {
-            localTools.add(webGroundingTools);
-            logger.info("Web Grounding enabled");
-        }
+        localTools.add(webGroundingTools);
+        logger.info("Web Grounding enabled");
 
         this.chatClient = chatClientBuilder
             .defaultSystem(SYSTEM_PROMPT)