Hans Leidecker
Self-employed
Experience
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
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
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
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
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
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++
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
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
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)
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
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
Industries Experience
See where this freelancer has spent most of their professional time. Longer bars indicate deeper hands-on experience, while shorter ones reflect targeted or project-based work.
Experienced in Transportation (20 years), Information Technology (4 years), Government and Administration (3 years), Insurance (3 years), Manufacturing (3 years), and Utilities (1.5 years).
Business Areas Experience
The graph below provides a cumulative view of the freelancer's experience across multiple business areas, calculated from completed and active engagements. It highlights the areas where the freelancer has most frequently contributed to planning, execution, and delivery of business outcomes.
Experienced in Information Technology (33 years), Business Intelligence (4 years), Quality Assurance (4 years), Product Development (4 years), and Accounting (1.5 years).
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
Profile
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