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Author: phax

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+.claude/
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CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+Phase2 (formerly "as2-lib") is a Java implementation of the AS2 protocol (RFC 4130) for secure document transport. It includes S/MIME signing/encryption, MDN handling (RFC 3798), and compression (RFC 5402). Forked from OpenAS2. Uses BouncyCastle for cryptography.
+
+## Build Commands
+
+```bash
+# Build all modules (skip tests for speed)
+mvn clean install -DskipTests
+
+# Build with tests
+mvn clean install
+
+# Run a single test
+mvn -pl phase2-lib test -Dtest=BCCryptoHelperTest
+
+# Build a single module
+mvn -pl phase2-lib clean install
+
+# Run demo webapp in Jetty (from phase2-demo-webapp)
+mvn jetty:run -pl phase2-demo-webapp
+```
+
+Java 17+ required. Uses Maven multi-module build with parent POM `com.helger:parent-pom`.
+
+## Module Architecture
+
+```
+phase2-lib          Core library: crypto, message model, processors, partnerships, client
+phase2-servlet      Servlet integration (AS2ReceiveServlet, MDN servlet)
+phase2-server       Standalone socket-based AS2 server with command system
+phase2-partnership-mongodb   MongoDB-backed IPartnershipFactory
+phase2-demo-webapp  Example WAR using phase2-servlet
+phase2-demo-spring-boot     Example Spring Boot app using phase2-servlet
+```
+
+Dependencies flow: `phase2-lib` ← `phase2-servlet` ← demo apps. `phase2-server` and `phase2-partnership-mongodb` depend only on `phase2-lib`.
+
+## Key Abstractions (phase2-lib)
+
+- **IAS2Session** (`com.helger.phase2.session`) — Central DI container providing access to certificate factory, partnership factory, and message processor. `AS2Session` is the concrete implementation.
+- **IMessage / IMessageMDN** (`com.helger.phase2.message`) — Message model hierarchy. `AS2Message` and `AS2MessageMDN` are the concrete types.
+- **IMessageProcessor** (`com.helger.phase2.processor`) — Orchestrates message processing through pluggable modules (sender, receiver, resender, storage). Uses chain-of-responsibility via `IProcessorModule` subtypes.
+- **ICertificateFactory** (`com.helger.phase2.cert`) — Certificate/keystore management. Implementations: `CertificateFactory` (keystore-based), `PredefinedCertificateFactory`.
+- **IPartnershipFactory** (`com.helger.phase2.partner`) — Partnership data store. Implementations: `XMLPartnershipFactory`, `SelfFillingPartnershipFactory`, `MongoDBPartnershipFactory`.
+- **ICryptoHelper / BCCryptoHelper** (`com.helger.phase2.crypto`) — Sign, verify, encrypt, decrypt, compress, MIC calculation.
+- **AS2Client** (`com.helger.phase2.client`) — High-level client API for sending AS2 messages. Uses `AS2ClientRequest`, `AS2ClientSettings`, `AS2ClientResponse`.
+
+## Processor Module Types
+
+Under `com.helger.phase2.processor`:
+- **Receiver**: `AS2ReceiverModule`, `AS2MDNReceiverModule`, `AS2DirectoryPollingModule`
+- **Sender**: `AS2SenderModule`, `AsynchMDNSenderModule`
+- **Resender**: `DirectoryResenderModule`, `InMemoryResenderModule`, `ImmediateResenderModule`
+- **Storage**: `MessageFileModule`, `MDNFileModule`
+
+## Configuration Patterns
+
+- **XML config** (server/servlet): `config.xml` defines certificates, partnerships, commands, and processor modules. See `phase2-server/src/main/resources/config/`.
+- **Programmatic** (client): Build `AS2ClientSettings` + `AS2ClientRequest`, call `AS2Client.sendMessage()`.
+- **Servlet handlers**: `AS2ReceiveXServletHandlerFileBasedConfig` (XML-based) or `AS2ReceiveXServletHandlerConstantSession` (code-based).
+
+## Test Patterns
+
+- JUnit 4/5 tests in standard `src/test/java` locations
+- `SPITest` classes in multiple modules verify service provider interface registrations
+- `Main*` classes are manual/integration test runners (not JUnit), e.g. `MainRunTestPhase2Server`, `MainTestClient`
+- Test utilities: `MockAS2KeyStore`, `MockCertificateFactoryByteArray` in phase2-lib tests
+- MongoDB tests use embedded Flapdoodle MongoDB
+
+## Code Conventions
+
+- Package root: `com.helger.phase2` (except Spring Boot demo uses `com.helger.as2demo.springboot`)
+- Follows [Philip Helger's Coding Styleguide](https://github.com/phax/meta/blob/master/CodingStyleguide.md)
+- Heavy use of `@Nonnull`, `@Nullable` (JSR 305/JSpecify) annotations
+- Relies on `ph-commons` library ecosystem (ph-commons, ph-web, ph-oton)
+- SLF4J for logging throughout; Log4j2 in server/demo modules