freiberufler Senior Java Developer auf freelance.de

Senior Java Developer

zuletzt online vor wenigen Tagen
  • 70‐75€/Stunde
  • 010452 Bucharest
  • auf Anfrage
  • ro  |  en
  • 31.05.2024

Kurzvorstellung

Software engineer/solutions architect - providing software development and architectural design consultancy, specialized in Java, Spring, microservices and AWS.

Qualifikationen

  • Amazon Web Services (AWS)
  • Docker
  • Hibernate (Java)
  • Java-Frameworks
  • Java (allg.)
  • Kubernetes
  • mySQL
  • Node.js
  • Software Architektur / Modellierung
  • Softwareentwicklung (allg.)
  • Spring

Projekt‐ & Berufserfahrung

Senior Java Developer
European Institution, The Hague
6/2023 – offen (1 Jahr, 1 Monat)
Innere und Äußere Sicherheit
Tätigkeitszeitraum

6/2023 – offen

Tätigkeitsbeschreibung

Contributed in building a resilient, horizontally scalable platform for managing biometric information.

⚙️ Critical data is scattered across multiple systems resulting in sluggish business processes and manual procedures.
? Developed unified application, integrating multiple services/APIs for key business flows.
✅ Automated multiple work procedures, resulting substantial increases in user productivity.

Tech Stack:
- Architecture: microservices.
- Backend: Java 17/21, Spring Boot, Spring Data, Spring Cloud, Spring JMS.
- Frontend: Vue.js.
- Database: Microsoft SQL Server.
- Caching: Redis.
- Messaging: RedHat AMQ.
- Testing: JUnit, Mockito, TestContainers.
- Cloud/containerization: Rancher, Kubernetes, Docker.
- Alerting: ELK.
- CI/CD: Azure DevOps.
- Libraries: Resilience4J, Lombok, Log4J2, MapStruct, SonarQube, OpenAPI.
- Integrations: ADFS.

Eingesetzte Qualifikationen

Softwareentwicklung (allg.)

Senior Java Developer
ShopYourWay, Home
10/2022 – 10/2023 (1 Jahr, 1 Monat)
Finanzdienstleister
Tätigkeitszeitraum

10/2022 – 10/2023

Tätigkeitsbeschreibung

Improved and maintained backend services for automated payments and reward programs.

⚙️ Improve performance, security, and reliability of existing partner file based integrations.
? Eliminated redundant processes, introduced at-rest file layer encryption for enhanced security and automated testing to ensure robustness.
✅ Reduced the volume of processed files by 50%, enhanced security twofold by introducing at-rest file encryption.
✅ Bolstered application reliability by 100% through automated testing.

⚙️ Extend and improve the current socket-based communication layer with external systems.
? Conducted a full-service refactor to enable segregated source IP and message type connection pools.
? Implemented Round Robin destination load balancing for efficient resource allocation.
✅ Achieved a twofold increase in flexibility, reliability and message throughput capacity.
✅ Enabled the system to manage and distribute load to twice as many connections compared to the previous configuration.

⚙️ Migrate multiple backend services from Oracle database to MySQL.
? Overhauled DDLs and DMLs.
? Updated configurations, queries, and application-specific code for MySQL compatibility.
✅ Improved overall application performance by 25-30% post-migration.

Tech stack:
• Architecture: hybrid.
• Backend: Java 8/11, WildFly, JBoss.
• Database: MySQL, Oracle.
• Testing: JUnit, Mockito, PowerMock.
• Libraries: Log4J, Slfj4J.
• Other: Sockets, Round Robin load balancing.

Eingesetzte Qualifikationen

Softwareentwicklung (allg.)

Senior Java Software Engineer
Clariness, Hamburg
6/2021 – 7/2022 (1 Jahr, 2 Monate)
Gesundheitswesen
Tätigkeitszeitraum

6/2021 – 7/2022

Tätigkeitsbeschreibung

Working part of the client's backend/software architecture team, my responsibilities included:
- research, design, code and document new microservices using event driven architectures
- develop functionality at the application level by integrating 3rd party APIs like Twilio or Mailjet
- improve exiting pipelines and build new ones
- handle production releases
- bug fixing

Tech Stack:
- Architecture: hybrid - monolith + microservices.
- Backend: Java 11/17, Spring Boot, Spring Data, Spring Web, Spring Cloud, Node.js 16, NestJs.
- Database: AWS Aurora PostgreSQL, AWS DynamoDb, Redis.
- Messaging: AWS SQS, AWS EventBridge.
- Testing: JUnit, Mockito, TestContainers.
- Cloud/containerization: AWS, Kubernetes, Docker.
- Alerting: Datadog, Sentry.
- CI/CD: Gitlab.
- Libraries: Resilience4J, Lombok, Log4J, Slfj4J, MapStruct, SonarQube, OpenAPI.
- Integrations: Twilio, Mailjet, Snyk, Auth0.

Eingesetzte Qualifikationen

Java (allg.)

Senior Java Software Engineer
Playtika, Bucharest
8/2020 – 6/2021 (11 Monate)
IT & Entwicklung
Tätigkeitszeitraum

8/2020 – 6/2021

Tätigkeitsbeschreibung

My time in Playtika was spent on the World Series of Poker project and revolved around two development cycles.

The first one involved migrating the current AWS cloud infrastructure on premise, which meant moving terabytes of data from our SQL/NoSQL databases. That was achieved using microservices as well as established solutions such as StreamSets resulting in minimal impact on the performance of the game.

The second challenge, was splitting the live monolithic system into a event driven, reactive, microservice architecture, extracting each functionality and rebuilding it using technologies such as Spring WebFlux and Apache Kafka.

Tech Stack:
- Architecture: hybrid - monolith + microservices.
- Backend: Java 8/11, Spring Boot, Spring Data, Spring WebFlux, Spring Cloud.
- Database: AWS DynamoDb, AWS AuroraDB, Aerospike, Mariadb.
- Caching: Redis, Memcached.
- Messaging: Apache Kafka.
- Testing: JUnit, Mockito, TestContainers.
- Cloud/containerization: AWS, Kubernetes, Docker.
- Alerting: ELK stack.
- CI/CD: TeamCity.
- Libraries: Lombok, Log4J, Slfj4J, MapStruct, SonarQube.
- Tools: Lenses, Swagger.

Eingesetzte Qualifikationen

Java (allg.)

Senior Java Software Engineer
Endava, Bucharest
1/2020 – 8/2020 (8 Monate)
IT & Entwicklung
Tätigkeitszeitraum

1/2020 – 8/2020

Tätigkeitsbeschreibung

At Endava, I worked on administrative platform focused on integrating multiple systems with the aim of providing a unified image over the logistics of an order, from placement to delivery. This was done by building an MVP that encapsulated the main business flows/functionalities, with special focus given towards creating a solid base structure for future developments.

Tech Stack:
- Architecture: microservices.
- Backend: Java 11, Spring Boot, Spring Data, Spring WebFlux, Spring Cloud.
- Database: Azure CosmosDb.
- Caching: Redis.
- Messaging: Azure Event Hubs.
- Testing: JUnit, Mockito.
- Cloud/containerization: Kubernetes, Docker.
- Libraries: Lombok, Log4J, Slfj4J, MapStruct, SonarQube.

Eingesetzte Qualifikationen

Java (allg.)

Software Engineer (Festanstellung)
Tremend Software Consulting, Bucharest
5/2016 – 12/2019 (3 Jahre, 8 Monate)
IT & Entwicklung
Tätigkeitszeitraum

5/2016 – 12/2019

Tätigkeitsbeschreibung

My time at Tremend Software Consulting was split among four projects. The first was an e-commerce platform where the architecture was based on microservices. My team developed an internationalization and customization service which enabled editors to translate and add content to the website. Also a media service was developed to enable asset management – mainly, cropping/storing images. Data fetched via a REST API was presented in an AngularJs application.

Next followed an internet banking solution. My role involved coding custom AngularJs widgets for the Backbase CMS and, also, developing the backend microservices which connected to the bank systems, aggregated and exposed data through REST APIs.

The third project I worked on a was multi-site, e-commerce platform built on top of the Magnolia CMS and Broadleaf Ecommerce. My job involved building an order fulfillment(checkout) microservice using Spring Boot, integrating the Adyen payment platform, accommodate the UPS Address Validation and Rating APIs, integrating the 2 platforms as well as the order fulfillment microservice (via Swagger generated libraries for client/server).

The last project I was involved in was an admin interface for marketplace platform aiming to automate the processes revolving vendor management and financial reporting. Architecture wise, we were using Spring Boot microservices that communicate through Apache Kafka pub/sub model. The CI/CD process is handled via Bamboo which builds and pushes Docker images into Google Cloud Repository, from which they are deployed and orchestrated though Kubernetes on the GCP.

Tech Stack:
- Architecture: microservices.
- Backend: Java 8/11, Spring Boot, Spring Cloud, Spring Data, Netflix Stack, PHP, Symfony.
- Database: MySQL, PostgreSQL.
- Caching: Redis.
- Messaging: RabbitMQ, Apache Kafka.
- Testing: JUnit, Mockito.
- Cloud/containerization: Kubernetes, Docker.
- CI/CD: Bamboo, Wercker, Jenkins.
- CMS: Magnolia CMS.

Eingesetzte Qualifikationen

Java (allg.)

PHP Developer (Festanstellung)
Machteam Soft, Bucharest
7/2013 – 5/2016 (2 Jahre, 11 Monate)
IT & Entwicklung
Tätigkeitszeitraum

7/2013 – 5/2016

Tätigkeitsbeschreibung

As part of the job, my main responsibilities were:
- analyzing business requirements, proposing technical solutions and implementing them.
- optimizing the application performance and refactoring the code to improve the quality.
- monitoring the application at the service level (MySQL, MongoDB) and identifying the issues/bottlenecks.

The project I worked on was a dating application. Some of the more interesting implementations I took part in are:
- registration process using 3rd party integrations: Facebook, Gmail and Yahoo
- users, events and transaction monitoring using Google Analytics.
- developing features for the app’s messaging system (alongside with a restriction system at the conversation level) plus integrating with RabbitMQ to persist the messages.
- implementing a friend referral system based on the email address and a bonusing algorithm for each invited friend.
- building a progressive email sending system based on priorities set for distributing a certain volume per IP address.
- developing an application that funnels users into the parent dating site.

Tech Stack:
- Architecture: monolith.
- Backend: PHP, Symfony 2, Zend Framework.
- Frontend: Twig, HTML, CSS, jQuery, PrototypeJs.
- Database: MySQL, MongoDb.
- Caching: Redis, Memcached.
- Messaging: RabbitMQ.
- Other: ElasticSearch.

Eingesetzte Qualifikationen

Software Architektur / Modellierung

Ausbildung

Batchelor's degree
University Politehnica
2014
Bucharest

Persönliche Daten

Sprache
  • Rumänisch (Muttersprache)
  • Englisch (Fließend)
Reisebereitschaft
auf Anfrage
Arbeitserlaubnis
  • Europäische Union
Home-Office
bevorzugt
Profilaufrufe
572
Alter
34
Berufserfahrung
10 Jahre und 11 Monate (seit 07/2013)

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