3.378 Jobs für Java in Deutschland

Present Technologies, ranked on the Top 25 of the Best Companies to Work for in Portugal, is seeking for highly-skilled Java developers to join our engineering team. From large-scale digital platforms to market-leading mobile apps, our clients and partners trust us to build reliable software used every day by millions of users.
If you are looking for challenging projects, this offer is for you!

WE are PRESENT because WE CARE!

ROLE DESCRIPTION - KEY RESPONSIBILITIES:

• Work closely with other engineers to deliver world class solutions that are scalable, survivable and consistent
• Passion for solving large-scale engineering challenges
• Dedication to complete projects on time
• Help the team evolve, sharing and experimenting new ideas and technologies

MAIN REQUIREMENTS:

• Highly experienced in developing using Java and Java EE technologies
• Experience in Object Oriented concepts, data structures and multi-threading
• Experience in modular architectures using Microservices
• Experience in web services development standards and best practices, including RESTful APIs and SOA services
• Experience in data architecture and design directed at relational databases and possibly with in-memory database(s)
• Experience with system integrations, optimising performance and data integrity
• Experience with Java Application servers (JBoss AS / WildFly will be valued)
• Experience with Unit and Integration testing using JUnit and Arquillian
• Experience with the Maven build automation tool
• Familiarity with Git source control system and tools such as GitHub or GitLab
• Good communication and organisational skills
• Proficiency in English

NICE TO HAVE:

• Familiarity with the Docker containerisation system
• Familiarity with DevOps tools and technologies
• Knowledge of infrastructure architecture design, including cloud-based infrastructure

PERKS:

• Healthcare Insurance
• Mobile phone
• Company/performance bonus
• Extra days of holidays
• Anual budget for flexible benefits (e.g. kindergarten payment, health and well-being, education expenses, savings & retirement, public transportation and family health insurance)
• Great offices with free fruit and coffee
• English lessons
• Technical training / learn sessions / workshops
• Udemy License
• Flexible working hours
• Work with a very talented team
• Prestigious clients
• Wellness measures
• Welcoming and relaxed work environment

Wallee is a payment technology company that enables merchants to accept omnichannel payments - whether online in web shops, on mobile devices, unattended kiosks or in physical outlets with terminals. Our software engineers are working on a variety of projects ranging from big data systems to dedicated merchant integrations. We’re driven by constantly improving the customer experience and enhancing the customer journey to satisfy our customers and consumers. We’re using latest technologies and tools.

Wallee requires a team of experienced and versatile software engineers to achieve our mission of providing the best payment experience to customers on the market. We use Scrum processes to organize our teams in multiple countries. We build technology leading payment systems that require a high degree of robustness, scalability and security. As we’re disruptors of the payment market we’re constantly pushing with our solutions into new areas.

• You develop and maintain integrations for our payment acceptance network and integrations into local acquiring platforms
• You write clean and good documented code or refactor existing code using the appropriate design patterns
• You transform our new products into software architecture and clean code that runs in our highly available and distributed environment
• You can take over responsibilities in the operations of a highly available, secure and distributed application.
• Research, conceive and develop software applications to extend and improve on our product offering.
• Write server-side code for web-based applications. Develop prototypes quickly and create robust high-volume production applications.

• Top notch English communication skills.
• You are highly committed and result-oriented.
• You bring working experience in architecting software in distributed and highly available environments.
• You have excellent discipline, pride and professionalism to write readable, documented and unit-tested code that serves as an example for those who study your work.
• You have at least 4+ years of programming skills in Java with good knowledge of the frameworks and tools: Spring Framework, JPA with Hibernate
• You have experience in using Eclipse or Intellij as a development environment. You can choose what you prefer.
• You have a good understanding of current encryption technologies experience in using web technologies (CSS, JavaScript, HTML)

• We offer a modern and safe working environment and workplace in the heart of the city, with career opportunities.

• You are part of an agile, young team and shape our products sustainably with your ideas.

• We are working with the most recent technology

• You will play a decisive role in designing products in an omni channel payment company and work with leading companies in the financial industry on international projects.

• As an innovative organization, we offer flexible structures and flat hierarchies.

• Cooperation with motivated colleagues and numerous personal development opportunities.

"We take the energy transition to the cities!" - With your help?

We believe that the energy transition doesn't have to be complicated. We offer municipalities, grid operators and energy suppliers the necessary decision-making and data basis for forward-looking planning of energy systems.

For the support in the field of Web Development we offer you a student position or an internship.

• Support the development of modern web applications
• Contribute to the design and implementation of interactive frontend features using JavaScript and React
• Work with geospatial data and energy-related datasets
• Help improve the overall codebase (frontend and/or backend)
• Support decision-making in energy-based online data applications

• You have experience or strong interest in JavaScript and React or similar frontend frameworks
• You are comfortable with or curious to learn about REST APIs, Python, and Django
• You are familiar with or willing to work with relational databases
• You work independently on challenging tasks
• You enjoy bringing in your own ideas, implementing them, and learning along the way

• Flexible hours: Whether you are an early bird or a late starter, you can schedule your working hours flexibly.
• Fair payment: We offer an attractive salary package.
• Great workplace: We work in a state-of-the-art office with top equipment, located in Freiburg.
• Team spirit: Both in your daily work as well as in regular after-work activities or company outings - you can look forward to a team of full-time employees and other working students in which you are fully integrated and enjoy your work from the very beginning.
• Career perspectives: Work in a sustainable, socially relevant and absolutely promising field.
• Personal training and development opportunities: We offer you the opportunity to quickly take on responsibility as part of a strong team and to grow in new and exciting activities.

"But why exactly greenventory?"

Together with us, you have the opportunity to realise projects in an ambitious team that will help shape the future. Through your work, you'll make an important contribution to advancing the energy transition and paving the way towards climate neutrality.

Sounds good? Apply now!

• Entwicklung und Implementierung von skalierbaren und wartbaren Java-basierten Anwendungen und Microservices.
• Mitgestaltung der Softwarearchitektur und technologischen Entscheidungen.
• Schreiben von unit-, integrations- und end-to-end-Tests zur Sicherstellung der Codequalität.
• Analyse und Behebung von Performance-Engpässen und Fehlern in Produktionsumgebungen.
• Durchführung von Code-Reviews und Mentoring von Junior-Entwicklern.
• Enge Zusammenarbeit mit Produktmanagern, UI/UX-Designern und anderen Stakeholdern.
• Bewertung und Integration neuer Technologien und Frameworks.
• Dokumentation von Designs und Implementierungsdetails.
• Beitrag zur DevOps-Kultur und Automatisierung von Build-, Test- und Deployment-Prozessen.
• Aktive Teilnahme an Scrum-Meetings und Sprints.

• Abgeschlossenes Studium der Informatik, Wirtschaftsinformatik oder eine vergleichbare Ausbildung.
• Mehrjährige praktische Erfahrung in der Java-Entwicklung, insbesondere mit Frameworks wie Spring Boot.
• Fundierte Kenntnisse in der Entwicklung von verteilten Systemen und Microservices-Architekturen.
• Erfahrung mit relationalen Datenbanken (z.B. PostgreSQL, MySQL) und/oder NoSQL-Datenbanken (z.B. MongoDB).
• Kenntnisse in Cloud-Plattformen wie AWS oder Azure sind von Vorteil.
• Vertrautheit mit agilen Entwicklungsmethoden (Scrum/Kanban).
• Starke analytische Fähigkeiten und eine strukturierte, ergebnisorientierte Arbeitsweise.
• Gute Kommunikationsfähigkeiten in Deutsch und Englisch.
• Bereitschaft, ein Hybrid-Arbeitsmodell zu nutzen.

We are seeking a Senior Full Stack Developer with strong experience in Java (Spring Boot) and React.js to join our team during a major digital transformation initiative. This is a greenfield project, where you will help design and implement a new component from the ground up, while also playing a key role in mentoring and guiding a team with mixed technical backgrounds.
You will work closely with a technical architect (English-speaking) who will set the strategic direction, while you take a leadership role in ensuring technical excellence, knowledge transfer, and best practices adoption across the team.
This position is ideal for someone who enjoys both hands-on development and coaching others, and who is motivated by building impactful, modern solutions in a collaborative environment.

• Lead the technical development of a new component using Java and React.
• Mentor and coach team members, upskilling them in full stack practices.
• Facilitate knowledge-sharing and collaborative learning within the team.
• Contribute to solution design, architectural discussions, and coding standards.
• Promote high-quality development practices, including testing and code reviews.

• 5+ years of professional experience as a Full Stack Developer.
• Strong hands-on expertise with Java (Spring Boot) and React.js.
• Proven experience mentoring or technically guiding other developers.
• Strong understanding of RESTful APIs and relational databases (PostgreSQL, Oracle).
• Familiarity with tools such as Docker, Git, and Postman.
• Excellent communication skills in English (both spoken and written).
• Passion for teaching, coaching, and enabling team growth.

• Competitive compensation based on experience and performance.
• Flexible working hours and the possibility of home office/remote work.
• Fully covered lunch allowance.
• Paid sick leave above statutory requirements.
• Annual wellbeing budget (increasing with tenure).
• Education and training budget, including language classes.
• Referral bonus program.
• Sick days and additional vacation for service anniversaries.
• Sabbatical leave options.
• Multisport card and support for fitness activities.
• International travel opportunities.
• Team-building activities and company events.
• Exciting challenges and career development opportunities in a dynamic environment.

WIR SUCHEN DICH.

Wir legen uns ins Zeug, damit Gamer Spaß haben. Die Interwebmedia GmbH ist seit über 10 Jahren auf dem Markt und betreut verschiedene kreative Projekte, die dafür sorgen sollen, dass Jung und Alt bei uns Zuflucht vor dem Alltag finden und einfach mal abschalten können. Uns gehört unter anderem eine der größten Minecraft Communities im DACH-Raum und haben nun zusätzlich eine eigene Agentur für weitere In-House Projekte gegründet. Wir verbinden flache Hierarchien mit ausgeklügelten Organisationsstrukturen und suchen nun jemanden, der unser Team ergänzt.

Deine Mission

Als Entwickler wirst du in einem kleinen Team zusammenarbeiten und deinen Input liefern, damit unsere User ein reibungsloses Spielerlebnis haben.

Dein Beitrag:

• Entwicklung und Erweiterung von Minecraft-Plugins
• Umsetzung eigenständiger Java-Anwendungen
• Wartung und Optimierung bestehender Systeme
• Analyse und Behebung von Bugs in Plugins, Serverfunktionen und Java-Komponenten
• Einarbeitung in bestehende Codebasen und externe Schnittstellen
• Unterstützung bei der technischen Konzeption neuer Features

Dein Profil

Must-Have Skills:

• Java (LTS-Versionen wie 17 oder 21): Tiefes Verständnis moderner Java-Konzepte wie Streams, Lambdas, Records, Optionals und asynchroner Verarbeitung (z. B. CompletableFuture) sowie fundierte Erfahrung im Umgang mit stabilen LTS-Versionen
• Backend-Entwicklung mit Java: Entwicklung modularer, wartbarer Systeme über REST-APIs, Event-Handling oder serviceorientierte Architekturen mit Fokus auf Skalierbarkeit und Lesbarkeit
• Spigot/Bukkit/Paper API (für Spiele- und Serverentwicklung): Entwicklung robuster Plugins auf Basis der Bukkit-, Spigot- oder Paper-API, inkl. Events, Commands, Permissions und Konfigurationshandling
• Thread-sicheres Arbeiten: Entwicklung sicherer Nebenläufigkeit mit `synchronized` Locks, Concurrent* -Klassen und CompletableFutures zur Vermeidung von Race Conditions
• NMS ( net.minecraft.server ) / Reflection: Umgang mit internen Minecraft-Klassen und Version-Abstraktion mittels Reflection zur Umsetzung tiefergreifender Funktionalität
• Protokollverständnis: Erfahrung im Umgang mit Minecraft-spezifischer Netzwerkkommunikation – entweder über Netty bei Low-Level-Zugriffen oder durch den Einsatz von ProtocolLib für Packet-Manipulation auf höherer Ebene
• Redis / Valkey (Live Messaging & Caching): Erfahrung mit Redis oder Valkey als In-Memory-Datenbank für Pub/Sub-Kommunikation, Session-State, verteiltes Messaging und Caching häufig genutzter Daten
• Performantes Arbeiten: Analyse und Optimierung von RAM-, CPU- und Tick-Zeit-Verbrauch durch effiziente Datenstrukturen, Caching, Lazy Loading und asynchrone Verarbeitung
• Git (Versionskontrolle): Versionssichere Entwicklung mit Git inkl. Branching, Pull Requests, Merge-Strategien sowie der Nutzung von Conventional Commits und Semantic Versioning
• Multi-Modul-Projekte (Maven): Strukturierung komplexer Projekte in einzelne Module (z. B. `api`, `com on , bukkit , bungee ) mit sauberem Dependency-Management
• MongoDB (Morphia): Arbeit mit dokumentenbasierten Datenbanken unter Verwendung des MongoDB Java-Treibers oder Morphia als ODM, inklusive Aggregationen, Indexoptimierung und performanter Abfragegestaltung
• REST-API-Entwicklung und -Anbindung: Erstellung und Konsumierung von RESTful APIs, inkl. JSON-Handling, Authentifizierung, Statuscodes und Schnittstellenstrukturierung
• Clean Code & Architektur: Anwendung von SOLID-Prinzipien, saubere Trennung von Verantwortlichkeiten, modulare Architektur sowie Best Practices für wartbaren und testbaren Code
• Fehleranalyse & Debugging: Systematische Identifikation und Behebung komplexer Bugs durch Loganalyse, Stacktrace-Interpretation, Tests und Runtime-Inspection
• Unit- und Integrationstests: Testabdeckung mit JUnit und Mocking-Frameworks wie Mockito sowie Integrationstests auf Systemebene
• Arbeiten mit externen APIs und Bibliotheken: Fähigkeit, sich eigenständig in fremde APIs einzuarbeiten, deren JavaDocs und Dokumentationen zu verstehen und korrekt in eigene Systeme zu integrieren

Nice-to-Have:

• Docker: Containerisierung von Java-Anwendungen und Services für lokale Entwicklung und Produktion, inkl. Docker Compose-Setups
• Linux-Server-Verwaltung: Grundkenntnisse in Linux-Administration (Ubuntu/Debian), inklusive Systemverwaltung, Netzwerkkonfiguration und Monitoring
• Deployment & Automatisierung (z. B. Ansible, GitHub Actions, GitLab CI): Aufbau und Pflege automatisierter CI/CD-Pipelines, Konfigurationsmanagement, automatische Tests und Versionsbereitstellung

• Betriebliche Weiterbildung
• Firmenhandy
• Flexible Arbeitszeiten
• Homeoffice-Möglichkeit
• Zusätzliche Urlaubstage
• Bonuszahlungen

• Design, implement, and maintain Java-based applications that can be high-volume and low-latency.
• Conduct software analysis, programming, testing, and debugging, while ensuring designs comply with specifications.
• Participate in all phases of the software development lifecycle and contribute to designing robust, scalable, and secure code.
• Collaborate with cross-functional teams to define, design, and ship new features, while actively participating in code reviews and providing constructive feedback.
• Maintain up-to-date knowledge of current technology trends, emerging technologies, and best practices in Java development.

• Bachelor's degree in Computer Science, Information Technology, or a related field.
• Minimum of 5 years of professional experience in Java development.
• Proficiency in Java frameworks such as Spring.
• Strong understanding of software development principles, including object-oriented design and design patterns.
• Excellent problem-solving skills and the ability to work collaboratively in a team environment.