Building an AI Agent System with the ReACT Pattern in Java

From answering questions to solving problems — Phase 6 of the Jarvis AI Platform After Phase 5, Jarvis could hear, speak, remember conversations, retrieve documents, and use tools. But every interaction was still limited to a single request and a single response. You: "What's the weather in Kathmandu?" Whisper ↓ AiOrchestrator ↓ WeatherTool ↓ Text-to-Speech Jarvis: "It is 22°C and clear." That works well for simple questions. It completely breaks down when a task requires multiple decisions. The Limitation of Single-Turn AI Imagine asking: Research the top 3 Java AI frameworks, compare them, and summarize the findings. A traditional chatbot usually replies: I don't have enough information to research that. The problem isn't intelligence. The problem is planning. To answer properly, the AI must: Search for Java AI frameworks Search for comparisons Gather information Analyze results Produce a summary That requires multiple tool calls and reasoning between each one. This is exactly what AI agents are designed to do. What Is the ReACT Pattern? ReACT stands for: Reason + Act Instead of generating one response, the AI repeatedly performs a reasoning loop. THINK ↓ ACT ↓ OBSERVE ↓ THINK ↓ ACT ↓ OBSERVE ↓ FINAL ANSWER Example: THOUGHT: I should search for Java AI frameworks. ACTION: search INPUT: Java AI frameworks 2026 ↓ OBSERVATION: Spring AI LangChain4j Semantic Kernel ↓ THOUGHT: Now I need comparison data. ↓ ACTION: search INPUT: Spring AI vs LangChain4j ↓ FINAL ANSWER Instead of guessing everything up front, the AI gathers information step by step before producing the final response. The Biggest Architectural Decision The most important design decision of Phase 6 was not modifying the existing chat pipeline . Instead of turning AiOrchestrator into a giant class responsible for both chat and agents, agents became a completely separate orchestration layer. ❌ Wrong AiOrchestrator ↓ Single Chat ↓ Agent Logic ↓ Tool Logic ↓ Everything Mixed Together ✅ Correct AgentController