Fred Hauschel-Senior Java Architect and Developer | Domain Architect (DDD, Knowledge Systems)

Recurring problem in my own AI-assisted projects: requirements analysis, use cases, and architecture decisions are created quickly with AI support, but they remain hard to trace and are scattered across Markdown files – knowledge is lost as soon as it is no longer in the context window. arknet turns requirements engineering and architecture knowledge into structured, verifiable data instead of plain text: requirements, use cases, and architecture decisions as a fully linked knowledge graph, traceable from the requirement to the architecture decision – queryable for both people and AI agents. Technically built on RDF/OWL and its own MCP server.

Result: MCP daemon running, Docker image automatically published to GHCR, nine hexagonal modules, eleven ADRs (including an open-core license model). Requirements engineering and ubiquitous language hexagon active. Public since 07/2026 as a Community Edition under Apache-2.0 (github.com/kogn-io/arknet), together with the Claude Code plugin and the GHCR image; open-core model.

Label: Java, Maven, RDF, RDF4J, OWL, SPARQL, Model Context Protocol, Spring AI, Docker, GitHub, Git, Claude Code, Obsidian, DDD, Hexagonal Architecture, ArchUnit, JUnit, AssertJ

Building a fully local on-premise AI environment for structured extraction from emails – local language models instead of tying myself to a major cloud provider. Evaluation of several local models on consumer hardware for suitability, quality, and resource usage, connection to my own Java application via Spring AI, and securing the model output through schema validation with a repair loop. Consistently DDD and Hexagonal Architecture.

Result: Running local setup on a used consumer GPU. Practical comparison under load: a small model solves the extraction in about 2.5 seconds per email (warm, 14-fixture benchmark); key finding that on such hardware the first question is VRAM (a much larger model was about seven times slower because it did not fully fit into GPU memory). Schema validation with a repair loop catches structurally broken output. Approach publicly described in a two-part specialist article on hauschel.de.

Label: Java, Eclipse, Spring Boot, Spring AI, Ollama, Claude Code, Docker, Git, GitLab CI, JUnit, jMolecules, DDD, Hexagonal Architecture, arc42, GitLab, Spring

Legacy analysis and modernization in an accounting product. Replacing an existing module, refactoring the historically grown integration code, and developing my own migration tool based on Spring Statemachine, built completely from scratch.

Coordination with different teams regarding implementation, tests, and interface

Documentation of the interface

Analysis of the existing interface

Code refactoring

Architecture refactoring

Architecture and development of the migration tool

Result: Running migration tool based on Spring Statemachine, analyzed and documented interface for the successor module, refactored integration code. Go-live after I had left the project.

Label: Java, Java Swing, Eclipse, Spring Boot, Spring Statemachine, ActiveMQ, SQL, Hibernate, Git, GitLab, Confluence, Jira, Scrum, Spring

Architecture of a microservice marketplace platform, split by business domains into organizations, solutions, orders, and offers (one service each).

Analysis of an existing platform and assessment of reusability/extensibility

Development/documentation of an architecture for a new platform (microservice)

Implementation of the first microservices to serve as a template

Connection to Keycloak, configuration via Keycloak REST API

Implementation of asynchronous task management based on ActivityPub

Result: Microservice architecture developed and documented; first microservices implemented as a template; asynchronous task management based on ActivityPub designed and implementation started; Keycloak integration via REST API.

Label: Java, Eclipse, Spring Boot, Spring WebFlux, RDF, JSON-LD, Turtle, RDF4J, ActivityPub, Keycloak, Docker, Maven, Git, GitLab CI, Testcontainers, Spring Config Server, Spring JPA, Confluence, Jira, Scrum, GitFlow, REST, Spring, DDD, Hexagonal Architecture, GitLab

Microservice that automatically places commercials in ad breaks based on rules; changes can be controlled via UI, rule violations are reported.

Initial setup of the project, with Continuous Delivery and integration into monitoring systems in close cooperation with the ops team

Design and development of automated ad optimization in the Scrum team

Importing commercials via REST interfaces

Coordination and implementation of the REST interface for the UI

Result: Productive microservice with Continuous Delivery pipeline and monitoring stack (Prometheus, Elasticsearch, Kibana); UI integration and rule violation reporting via REST.

Label: Java, Eclipse, Maven, Spring Boot, REST, Postman, Docker, AWS, Git, GitLab CI, Jira, Confluence, Prometheus, Elasticsearch, Kibana, Terraform, Scrum, GitLab, Spring

Over a little more than two and a half years, a continuous line toward test automation across several projects built on top of each other. Starting with the analysis of the development and QA departments working separately (different tools, high redundancy), then a test framework for development that QA later took over and expanded. Across the projects, quality, reporting, and cooperation between both departments improved significantly.

Analysis of the current situation in development and QA, development of improvement proposals

Design and implementation of the test frameworks

Reporting by linking the test framework, Jira, and HP Quality Center / HP ALM

Advising internal staff on development and architecture topics

Introduction of agile methods and Jira, optimization of reporting options

Communication with a wide range of stakeholders, convincing others of proven approaches

Result: Built a shared test framework for development and QA that was still in use as of mid-2026 (confirmed in July 2026 by a colleague from the test department). Reporting integration with HP Quality Center / HP ALM, introduction of Jira in QA.

Label: Jenkins, Java, Eclipse, Groovy, JUnit, Spock, Maven, Nexus, SVN, Concordion, SoapUI, HP Quality Center, HP ALM REST API, Jira, Scrum, Confluence

Process consulting for defining IT incident and change management processes supported by Jira, including defining a new interface between the service provider's issue tracker and Jira. Advising management as well as front, middle, and back office on process design, Jira customization, and selecting service providers.

Advising management as well as front office, middle office, and back office

Supporting stakeholders in designing the incident and change management processes

Support in adapting Jira to the processes and selecting additional external service providers

Label: Jira, Scrum, Confluence, Gliffy, Enterprise Architect

Reorganization of the runtime environment: 5 products across 6 environments at the hardware provider, turning a fragmented infrastructure into a unified setup. Reworked and standardized the build process, software structure, and development and rollout processes, and updated frameworks/libraries and the database.

Analysis of the existing infrastructure, software, processes, and documentation

Planning and monitoring of the new infrastructure according to the bank's requirements

Coordination of various teams

Optimization and documentation of the software lifecycle process

Migration of the existing software to new structures and frameworks or libraries

Moving redundant code into central libraries

Introduction and development of tools for monitoring the infrastructure

Label: Java, JBoss (v7.1), Oracle (v11g), Jetty, Hibernate (v4), Spring (v3.1), Maven (v3), Nagios, Jenkins, Sonar, Nexus, SVN, XML, XMLBeans, Enterprise Architect, Eclipse, Redhat Linux, Lotus Notes, SQL, Windows

Build reorganization for 21 web applications and 30 libraries: the existing Ant build is being moved to Maven 3, made simpler and more flexible, and integrated into continuous integration (Hudson), with the goal of automatically generating documentation and metrics. The migration runs through a script that sets up the Maven-compliant project structure without interrupting maintenance and further development and while keeping the SVN history.

Analysis of the existing build management

Optimization and mapping of the development and build processes

Design of build management in Maven 3

Creation of an Ant migration script (svn4ant) that restructures the project to match Maven conventions and preserves the SVN history

Implementation of the new build process

Automatically generated documentation and code metrics (Javadoc, Xref, PMD, FindBugs, Checkstyle, Cobertura/code coverage, dependencies, release notes)

Quality assurance and refactorings on the legacy code

Result: Reorganized build landscape (Ant → Maven 3), automated metrics, SVN history preserved.

Label: Java, Ant, Maven (v3), Hudson, Proximity, PMD, FindBugs, Checkstyle, Cobertura, SVN, Tomcat (v6), Eclipse, JUnit, Servlets, JSP, Struts, XML, Apache Commons

Cross-product redesign of a logistics platform that had grown over many years and was highly complex: the existing PL/SQL solution is being replaced by a message-based architecture based on Enterprise Integration Patterns (Gregor Hohpe). The goal is modularization to reduce errors in releases and create a flexible basis for future requirements.

Design of the cross-product logistics redesign

Replacement of the PL/SQL logic (extraction from the order management system, delivery note to the logistics provider) with a messaging architecture based on EIP

Documentation of the architecture with Gregor Hohpe's pattern symbols to make the reference to the literature clear

Result: Logistics platform converted from PL/SQL to a message-based architecture (EIP).

Label: Eclipse, Java (v1.4), Maven (v2), Archiva, SVN, Web Services, WSDL, XSD, XML, Mantis, Oracle OC4J, Confluence, Enterprise Architect, Enterprise Integration Patterns, Share Point, UML, SQL, Oracle

Expansion of the installation service into a "full-service installation concept": through installer software (installer CD) that guides the customer or service technician through the installation, registration, login, ordering and download of the security package, product information, as well as setup and ordering of messaging and hosting are covered.

Replacing the PHP service with a Java implementation

Creating a new library for authentication and authorization that will replace the hard-to-maintain legacy code in the medium term and will also be offered as a web service

Extracting the password validation logic from the legacy code and making it reusable for existing and new libraries

Connecting existing, partly external web services

Result: Replaced the PHP service with a reusable Java service and auth library.

Label: Eclipse, Java (v1.4), Maven (v2), Archiva, SVN, Web Services, WSDL, XSD, XML, Apache Commons, Spring, Clear Quest, Tomcat (v5), Oracle OC4J, Confluence, Enterprise Architect, UML

Improved the development process in a heterogeneous IT landscape that had grown over many years, with development spread across many teams. As architect and interface between the project stakeholders, brought the technology up to date and prepared innovations that created both technical and business value; took a leading role in the middleware team for agent and customer portals.

Established a property management process, all properties maintained centrally and split by environment into .zip files during the build, with a uniform and interchangeable access mechanism via Spring and Apache commons-config

Introduction of Maven 2 and the build process it defines

Information portal based on a meta model (environments, development plans, artifacts, releases) – shows Maven artifacts with versions, release notes, metrics, documentation, and target/actual setup, with navigation from the environment down to the source code

Introduction of a Confluence wiki for documenting the software artifacts

Introduction of state-of-the-art technologies such as Axis 2 and Spring

Model-driven software development through a self-developed DSL used to describe interfaces in an abstract way; a generator creates complete technical software parts from this using templates (including a WSDL generator), so developers can focus on business logic

Result: Modernized build and tool chain (Maven 2, own DSL with xtext/xpand, information portal with meta model).

Label: Eclipse, Java (v1.4), Ant, Maven (v2), Archiva, SVN, CVS, Axis (v1), Axis (v2), Web Services, WSDL, XSD, XML, Servlets, JSP, Struts, Spring, Spring LDAP, OpenArchitectureWare, xtext, xpand, Tomcat (v5), Confluence, Enterprise Architect, UML, Apache Commons, Clear Quest, Quartz

Further development of a web-based customer advisory software in a multi-layer architecture: the web application captures the financial situation, evaluates it, and offers products; together with other channels, it accesses the same middleware.

Analysis of the current state (architecture review, assessment of the specification, evaluation of the development model and tests) and recommendations for the next steps

Development of an alternative architecture proposal

Support with tool selection and recommendation of the development environment

Advice on industry-specific and application-specific topics

Work on taking over the web application (especially middleware integration)

Representing the technical view in meetings with the large bank

Initiative for closer collaboration with the team of the parallel project

Result: Architecture review and alternative proposal; support with taking over the web application (middleware integration).

Label: Java, Eclipse, CVS, Ultraedit, Java (v1.3), Tomcat (v4.1), Struts, Apache Commons, Enterprise Architect, Windows, UNIX

The historically grown source code organization of a bank no longer meets the requirements and is being restructured according to the latest JBF guidelines; special feature: the change had to be completed in one day.

Analysis of the source code organization

Planning of the refactoring

Development of the guidelines for the move and support of the source code migration within CVS

Refactoring, testing, and go-live

Provision and support of the Eclipse development environment

Label: Java, Eclipse, CVS, Ultraedit, Java (v1.3), JBF (v4.15), Windows, UNIX

Modernization of the loan processing application (continuation of the 2001 project): brought up to date with the latest Java Banking Framework and the previous HTML interface replaced by a JBF Swing client started via WebStart. The three-tier application (client, server, backend) communicates in the server layer via XML with the Lotus Notes backend.

Technical analysis of the interface between client and server

Design of the interface

Design and implementation of the server layer

Label: Java, Eclipse, CVS, Ultraedit, Java (v1.3), Tomcat, JBF (v4), XML, Lotus Notes, Windows, UNIX, HTML

Replaced an existing loan processing application with a future-proof application using Java, Servlets, and JBF – with an import interface and connection to a complex host application using standard patterns (GoF).

Technical analysis

Design of an import interface

Design and implementation of the connection to a complex host application using standard patterns (GoF)

Label: Java, JBuilder, Ultraedit, Java (v1.1), JBF (v3), Servlets, CVS, Windows

Expansion of the internet presence and migration of the finance portal from Microsoft COM to J2EE; the tasks arose within a complex project landscape based on individual topics.

Requirements analysis: requirements catalog together with the business department and web designer, technical consulting, reporting to the overall project manager, team lead

Project planning and organization: contribution to the overall technical project plan, schedule and resource planning, onboarding of team members, communication between end customer, client, and subcontractors

Connection of a host system to the new portal: analysis of the existing connection, design of a new J2EE-compliant solution, onboarding of the development team, leading the development of a test framework

Connection of a market data provider via XML: design and implementation of an XML interface in Java via a J2EE-compliant platform (Enterprise JavaBeans) up to the web tier

Integration of client and server: connection of static HTML pages to the middleware via JSPs, creation of test JSPs

Result: finance portal migrated from MS COM to J2EE; J2EE-compliant host connection designed; XML interface to the market data provider designed and implemented; securities subteam built and led.

Label: Java, Kawa (v4), Ultraedit, Homesite, TogetherJ (v4), Java (v1.2), Tomcat, BEA Weblogic (v5.1), abaXX ebs, abaXX JSP-Framework, PVCS (v6.5), Oracle (v8i), TOAD, Windows, HTML, JSP, UML, XML

A Java application is to transfer program schedule data from a TV channel from an XML file into a database.

Design and implementation of the Java application

Graphical display of the data using HiGrid classes (KL-Group)

Testing, maintenance, and enhancement

Label: Java, Java Swing, JDBC, XML, Informix, Windows