ACHILLEAS KALKATZAKOS available

ACHILLEAS KALKATZAKOS

Senior Software Engineer

available
Profileimage by ACHILLEAS KALKATZAKOS Senior software engineer from Duesseldorf
  • 40210 Duesseldorf Freelancer in
  • Graduation: not provided
  • Hourly-/Daily rates: not provided
  • Languages: German (Elementary) | English (Full Professional) | Greek (Native or Bilingual)
  • Last update: 28.08.2013
KEYWORDS
PROFILE PICTURE
Profileimage by ACHILLEAS KALKATZAKOS Senior software engineer from Duesseldorf
SKILLS
• Many years of professional experience in designing, developing, and supporting applications
• In depth knowledge and practical experience of Core Java and of various Java based open source frameworks
• Agile methodologies and tools
• In depth knowledge of design patterns and object oriented design
• Solid knowledge of relational database design principles and data modeling.
• Practical experience with core Web technologies and frameworks
• Good communication, team working and social skills
REFERENCES
September 2012 – March 2013, June 2013: Lead Developer
Düsseldorf, DE
Vodafone Global Services – ITHR Consulting

Super mobile Home Screen Editor (see description in the previous role)

• Led the Editorial stack of applications for project Super mobile Home Screen from September 2012 driving the design and implementation for 2 major upgrades for the Android Editor and for the first release of Windows Phones Editor.
• Implementation of new features using TDD and addition of JUnit tests in untested parts of the application improving test code coverage and reducing bugs.
• UI improvements by major application refactoring for long running back end operations by changing them to asynchronous using the improved java 5 concurrency libraries.
• Close cooperation with business analyst to define new requirements and specifications
• Showcase presentations to stakeholders at the end of each development sprint.
• Support, Testing and Debugging during BAU (Business As Usual)

Technologies used: Java, Spring MVC/AOP, Hibernate/JPA, Oracle, SQL/PLSQL, Groovy (testing), Scrum, Maven, GIT, Jenkins, JUnit, TDD, GWT/SmartGWT, JQuery/Javascript, HTML/CSS

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April 2008 – August 2012: Senior Software Engineer
Düsseldorf, DE
Vodafone Global Services – ITHR Consulting

Super mobile Home Screen Editor: a set of web based editing tools for project Super mobile Home Screen (Vodafone Discover App) that delivers a widget across all Vodafone Opcos personalized with content always fresh and downloaded in background. The editor is used to configure each country’s content and has evolved over the years into three separate web applications for Android/Windows tablets/Windows Phones. The tools have login functionality and editors with roles per country are configured by another web application. The tools are Front end based on GWT/SmartGWT or JQuery and back end based on Spring/Hibernate/Oracle.

• Migration of the editors/roles/countries configuration functionality to its own web app based on a new architecture using JQuery and Spring MVC controllers.
• Implementation of new features for an upgrade of the Android Editor (SmartGWT/GWT based)
• Design and implementation of many modules for the Windows Tablets Editor which was a new product based on new technology stack (JQuery + Spring MVC)
• Support, Testing and Debugging during BAU (Business As Usual) phase.

Technologies used: Java, Spring MVC/AOP, Hibernate/JPA, Oracle, SQL/PLSQL, Scrum, Maven, GIT, Jenkins, JUnit, TDD, GWT/SmartGWT, JQuery/Javascript, HTML/CSS

Integration Proxy: a back end engine that provided services like content retrieval, encryption, billing, authentication/authorization and transformation, powering a various of Vodafone products like Vodafone Music, Vodafone Shop, Vodafone MyWEB and Vodafone 360. Back end system based on OSGi and Spring DM.
• Design and implementation of an OSGI based billing gateway to handle country charging. The system was composed of a set of OSGI bundles that connected with the Vodafone legacy billing systems (ER) of each country and provided two APIs an XML based and a REST.
• Delivery of country purchasing customizations such as different purchase flows or subscriptions handling. Each country customization lived in its own OSGI bundle achieving highest degree of modularization.
• Close cooperation with business analyst to define new charging requirements and specifications.
• Performance improvements in user purchasing experience by pre caching prices of products, as the Vodafone legacy billing system was slow under heavy load.
• Delivery of Fitnesse acceptance tests and implementation of a fixture and a billing system stub to handle full flow purchases testing resulting in automated standalone full user purchase acceptance test.
• Support, Testing and Debugging during BAU (Business As Usual) phase.
• Low Level Design documentation

Technologies used: Java, Spring, Scrum, Maven, GIT, Jenkins, OSGI, Spring DM, JUnit, TDD, XML/Castor, Fitnesse

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July 2006 to April 2008: Senior Software Engineer
Newbury, London UK
Vodafone Global Services – SLA Mobile

Vodafone Live! (described in an older job position) - Countries’ software localizations project.
• Redesign of countries localizations for their proper upgrade to the latest software global release
• Close communication with the Country’s solution engineers to analyze and define the specifications for every existing country’s software localization.
• Implementation of countries localizations based on the latest global software release on a common code repository server.
• Delivery of design documents for all software localizations.
Technologies used: Java/J2EE, JUnit, Weblogic application server, Oracle, Struts

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December 2005 to July 2006: Senior Software Engineer
Düsseldorf, DE
Vodafone Global Services – SLA Mobile

Vodafone Live! (described in an older job position) - Migration to central servers of the system hosted in Greece.
• Upgrade of country’s portal software into latest release and migrated existing GR software customizations to the new global software release.
• Technical advice to country and Global operations personnel to assure smooth migration for all the billing related functionality.
• Automated acceptance tests based on JUnit to verify correct billing functionality after the migration.
Technologies used: Java/J2EE, JUnit, Weblogic application server, Oracle, Struts

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September 2005 to December 2005: Senior J2EE Engineer
Athens, GR
Trasys Greece, Ltd.
PIM (Product Information Management) is a project of the European Regulatory Authorities (EMEA) to have a standardized, electronic process of submitting and reviewing product information for new and existing pharmaceuticals.
• Implementation and improvements for critical front end and back end modules of the system
Technologies used: Java, J2EE, EJB, Struts, Oracle, Derby

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October 2002 to September 2005: Software Engineer
Athens, GR
Vodafone GR

Vodafone Live!: A web applications platform for mobile telecommunication devices. It offers multiple services to mobile telephones such as e-shopping, video and image downloads, internet access, mobile TV, email etc. It has been deployed to many mobile operators globally and is supported and marketed extensively. I was involved with Vodafone Live from its very first release in Greece.
• Design and implementation of a software module connecting the global Vodafone content billing system (ER) with the local OpCo’s (Greece) billing systems so as to successfully charge users when they do content purchases through their mobile phones.
• Implementation of the billing WAP front-end to support purchasing and self-care.
• Installation and maintenance of every other application that comprised the ER billing system.
• Troubleshooting and bug fixing (Business As Usual)
Technologies used: Java/J2EE, Weblogic application server, Oracle, Struts

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February 2002 to September 2002: Software Engineer (military service)
Athens, GR
Hellenic Army General Staff

Live weather data project. The project retrieved/stored and displayed real time weather conditions for the area and nearby places of Greece.
• Implementation of the back end code fetching live weather data from an external source and saving them locally in a database
Technologies used: ORACLE9i Database Server, Embedded SQL, SQL/PLSQL, TUXEDO middleware, C programming language.

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September 1999 to May 2001: Software Engineer
Athens, GR
Intrasoft International
TCP: the Transit Computerization Project aimed at specifying, developing, deploying and supporting the operation of the New Computerization Transit System - a system that will support the Customs Community / Common Transit procedures associated with the movement of goods in transit within the EU, EFTA and í4 countries.
• Development of several software modules for two of the applications of the project, a message translation/forwarding server based on the TUXEDO middleware and a Java Swing testing tool.
• UAT support on client’s site for a major release of the project
Technologies used: C, Java, Swing, SQL, Oracle, TUXEDO
TIME AND SPATIAL FLEXIBILITY
100% available
OTHER
Java: Core, EE, Spring framework/technologies, OSGI, AOP, SOA, Groovy
Agile methodologies: TDD, Continuous Integration, Scrum, Kanban
Mobile platforms: Android
Web frameworks: Spring MVC, Struts
Testing frameworks: JUnit (+JMock, Mockito), Fitnesse
Continuous Integration: Jenkins
ORM: Hibernate, JPA
IDE: STS/Eclipse, Netbeans, Intellij
J2EE app/web servers: JBoss, Tomcat, Jetty, Apache Felix
Build/management tools: Maven, Ant
Project Management Tools: TeamForge, HP Quality Center, Trello
Source Version Control: CVS, SVN, GIT
Web technologies: GWT/SmartGWT, Servlets/JSP, JavaScript, JQuery, HTML/CSS, Ajax, XML/XSLT
Databases: Oracle, MySQL, SQL/PLSQL
Operating systems: Linux/Unix, Mac OSX
Other: C
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