Hans Leidecker - Self-employed

Q: Where is Hans based?

Hans is based in Buchen, Germany and can operate in on-site , hybrid , and remote work models.

Q: What languages does Hans speak?

Hans speaks the following languages: German (Native), English (Elementary) .

Q: How many years of experience does Hans have?

Hans has at least 33 years of experience. During this time, Hans has worked in at least 1 role and for 10 different companies . The average length of individual experience is 3 years . Note that Hans may not have shared all experience and actually has more experience.

Q: What companies has Hans worked for in recent years?

In recent years, Hans has worked for Public Administration and Insurance .

Q: Which industries is Hans most experienced in?

Hans is most experienced in industries like Transportation , Information Technology , and Government and Administration . Hans also has some experience in Manufacturing , Insurance , and Utilities .

Q: Which business areas is Hans most experienced in?

Hans is most experienced in business areas like Information Technology , Product Development , and Business Intelligence . Hans also has some experience in Quality Assurance and Accounting .

Q: Which industries has Hans worked in recently?

Hans has recently worked in industries like Government and Administration and Insurance .

Q: Which business areas has Hans worked in recently?

Hans has recently worked in business areas like Information Technology and Business Intelligence .

Recommended expert

Buchen, Germany

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Experience

Jan 2022 - Dec 2024

3 years

Public Administration

Developed web services for processing vehicle registrations (registration, transfer of ownership, deregistration)
Implemented with Spring Boot, JMS (ActiveMQ), Oracle, Tomcat/JBoss, TomEE, OpenSearch

Jan 2021 - Dec 2021

1 year

Insurance

Migrated large data sets from Adabas with transfer to a REST interface in OpenShift
Developed microservices for a data warehouse with interfaces to and from enterprise applications
Developed REST services with HAL
Implemented with Java 11, Spring, Oracle, OpenAPI, OpenShift, Kafka

Jan 2004 - Jun 2005

1 year 6 months

Water Management Association

New development of a multi-layer application for billing water consumption, sewer fees, disposal, installation orders, and integrated accounting software (general ledger, accounts receivable, accounts payable)
Took over and prepared the data from the predecessor software
Interface to E-Post; PDF archive
Implemented with Java (Swing, Vaadin), RMI, JDBC; DB: MS SQL Server

Oct 2003 - Dec 2003

3 months

Landscape and Gardening Company

Ported software for invoicing, payment monitoring, cost accounting, payroll, and estimates to Delphi 8 for Windows XP and MS SQL Server 2000
Implemented with Object Pascal (Delphi 8); DB: MS SQL Server

Jan 2001 - Dec 2020

20 years

Deutsche Bahn

Developed and maintained (refactoring) the CFP timetable planning system based on the J2EE architecture: application components, interfaces; WebLogic, entity beans, message-driven beans, session beans, JAX-RPC, XSLT; Java rich client with Swing, RPC; DB: Oracle, DB2
Developed and maintained (refactoring) software for train monitoring (FplV-ZugUE/TraCE): client and server components with Swing, J2EE; CTG; batches and services for MVS/CICS; concept for authorization control with LSO; multi-tenancy; WebLogic with Spring, Ibatis/MyBatis, JAX-WS, JAXB, CTG, FTP; DB: Oracle, DB2, PostgreSQL
Designed, developed, and maintained/extended Hermes (HERM-LSO) for international exchange of train data: HTML/JSF, J2EE; CTG; Cobol batches, CICS online modules, XML parser, MQ Series; JBoss, Spring, Hibernate, CTG; DB2
Migrated the message hub Comgate to the Amazon cloud with Java, C, RTE, Python, shell; Tomcat 9, TradeXpress, Amazon DynamoDB, Connect:Direct, MQ Series
Maintained and enhanced CAM FplV with Cobol, MQ Series, DB2
New development of software to handle port orders for MVS/CICS (Natural, Adabas)
Modeled a data mart for punctuality measurements (PME); created technical interface and component specs; implemented ETL processes with Enterprise Architect, Java, JBoss, Spring, Ibatis; Java rich client with Eclipse RCP; DB: Oracle
New development of software for managing empty railcars (EWDS) with integration of a route optimizer developed in C++: Java, C++, JSF; JBoss, Spring, Hibernate, JNI; DB: Oracle
Technical upgrades: WebLogic up to 12.2.1, JBoss EAP up to 7.2.2, Java up to 11, OpenJDK, MQ Series; migration from RichFaces to PrimeFaces; processes: LSO-LSO, SD-LSO, GWD, GWVA, CDD, RST, PME, HERM-LSO, SVI, TraCE, ZuBA, CFP
Extended the LSO-LSO software with additional validations to protect against XSS attacks using Java and ESAPI

Nov 2000 - Dec 2000

2 months

Grundstücks-Treuhand-Gesellschaft

Porting a property statistics application to Windows NT with MS SQL Server 7
Designing and setting up the database; porting data from Unix/ISAM to Windows NT
Designing the user interfaces; modeling; implementation in C++

Jan 2000 - Dec 2000

1 year

Bausparkasse

Developing a home savings calculator for Windows 2000
Modeling; developing and testing a platform-independent calculation core to simulate contract progress and contract changes
Developing a test program for automated testing of the calculation core
Implemented in Java

Jan 1998 - Dec 1999

2 years

Versicherungsverband

Independently developing a graphical editor for an object-oriented database
Modeling; programming with Java (Swing) on OS/2, Unix, Windows
Development on Windows using JBuilder2, on OS/2 with text editors
Proprietary database access classes for other projects

Jan 1996 - Dec 1998

3 years

Kugellager-Fabrik

Developing software to monitor staff qualifications and to collect and analyze production data
Windows network with OS/2 server, Windows 3.1x/NT/95
Implemented in Object Pascal (Delphi)

Jan 1990 - Dec 1992

3 years

Siemens-Nixdorf AG

Assisting with porting the standard software for OPEL dealers from the Nixdorf Quattro system to Unix
Using self-developed porting tools and database

Jan 1989 - Dec 1990

2 years

Self-employed

Development of a compiler to translate BASIC programs for Nixdorf Quattro into C for Unix
Development of tools to convert files from Quattro format to Unix format
Development of an index-oriented database for Unix to facilitate porting
Development of a user-friendly print spooler for Unix

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Transportation, Information Technology, Government and Administration, Insurance, Manufacturing, and Utilities.

Transportation

Information Technology

Government and Administration

Insurance

Manufacturing

Utilities

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Business Intelligence, Quality Assurance, Product Development, and Accounting.

Information Technology

Business Intelligence

Quality Assurance

Product Development

Accounting

Skills

Programming Languages: Java, C++, C, Javascript, Cobol, Object Pascal (Delphi), Basic, Sql, Pl/Sql, Rte, Python, Xslt
Frameworks: Java Ee (Ejb 1, 2, 3), Jax-Rs, Jax-Ws, Jax-Rpc, Jms, Spring, Ibatis/Mybatis, Hibernate, Swing, Java Fx, Vaadin, Eclipse Rcp, Jsf 2, Primefaces, Richfaces
Application Servers: Weblogic, Jboss Eap, Tomcat
Tools: Eclipse, Spring Tool Suite, Intellij Idea, Android Studio, Netbeans, Enterprise Architect, Eclipse Papyrus, Maven, Gradle, Ant, Liquibase, Jenkins, Artifactory, Clearcase, Clearquest, Git, Subversion
Industries: Car Trade, Building Societies, Construction Companies, Energy Utilities, Wholesale, Manufacturing, Public Administration, Transport Companies (Deutsche Bahn), Insurance
Databases: Oracle, Db2, Ms Sql Server, Postgresql, Opensearch, Object-Oriented Databases, Amazon Dynamodb
Focus Areas: Independent Development Of User Software And Tools, Object-Oriented Modeling/Development (Uml), Refactoring, Java, Java Ee

Languages

German

Native

English

Elementary

Statistics

Experience

Total positions 11

Experience in Transportation 20 y

Avg length 3 y 3 m

Longest experience 19 y 11 m

Expertise

Recent roles Self-employed

Main industries Transportation, Information Technology, Government and Administration

Main business areas Information Technology, Business Intelligence, Quality Assurance

Profile

Created

August 2025

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Frequently asked questions

Have questions? Find more information here.

Hans is based in Buchen, Germany and can operate in on-site, hybrid, and remote work models.

Hans speaks the following languages: German (Native), English (Elementary).

Hans has at least 33 years of experience. During this time, Hans has worked in at least 1 role and for 10 different companies. The average length of individual experience is 3 years. Note that Hans may not have shared all experience and actually has more experience.

Based on recent experience, Hans would be well-suited for roles such as: Self-employed.

In recent years, Hans has worked for Public Administration and Insurance.

Hans is most experienced in industries like Transportation, Information Technology, and Government and Administration. Hans also has some experience in Manufacturing, Insurance, and Utilities.

Hans is most experienced in business areas like Information Technology, Product Development, and Business Intelligence. Hans also has some experience in Quality Assurance and Accounting.

Hans has recently worked in industries like Government and Administration and Insurance.

Hans has recently worked in business areas like Information Technology and Business Intelligence.

Hans is immediately available for suitable projects.

Hans's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.

To hire Hans, click the Meet button on the profile to request a meeting and discuss your project needs.