Java turned 30 in 2025 and still holds a top-four position in every major programming language ranking. Over 90% of Fortune 500 companies rely on Java for core backend systems. More than 418,000 companies globally use it. The Stack Overflow Developer Survey 2025 found that 30.35% of developers use Java regularly, and 39.5% of recruiters actively seek Java skills. Java is not in decline. It remains the language that enterprise software, financial systems, logistics platforms, healthcare infrastructure, and large-scale web applications are built on, because it delivers the stability, type safety, and long-term maintainability that critical systems require. When you hire Java developers from KiwiCommerce, you get UK-based specialists in Spring Boot, enterprise Java backends, REST APIs, and Java web applications, built on current LTS versions to standards that hold up at scale.
Java's strength is in enterprise-grade, long-lived systems where correctness, performance, and the ability to maintain the codebase across multiple developers and years of change matter more than rapid prototyping speed. Our dedicated Java developers work with businesses that are building or maintaining exactly those kinds of systems.
Get In TouchLarge organisations with existing Java backends, or those building new enterprise systems on Java and Spring Boot. These projects require Java developers who understand the Spring ecosystem in depth, can work within established Java conventions, and make architecture decisions that keep complex systems maintainable over multi-year development cycles. Our dedicated Java developers work on enterprise backends the way they deserve to be built.
Spring Boot is the leading framework for Java REST API and microservices development. Our Java web developers build Spring Boot APIs with proper layering, DTO and entity separation, Spring Security authentication, JPA and Hibernate database integration, and the testing coverage that production APIs require. For microservices architectures, we add Spring Cloud for service discovery, configuration management, and distributed tracing.
Enterprise eCommerce platforms built on Java, including custom backends, order management systems, product catalogue engines, and the integration layer between a frontend and a Java-backed commerce system, need developers who understand both the Java stack and the eCommerce domain. Our Java app developers bring both.
Java 8 and Java 11 applications still running in production represent a real security and maintenance risk as the ecosystem moves forward. These systems need developers who can read and understand existing Java code before changing it, identify what is worth preserving, plan a migration to Java 21 or Java 25 LTS, and execute the upgrade in stages without destabilising live systems.
Java is a strongly typed, object-oriented, platform-independent programming language first released in 1996 by Sun Microsystems (now Oracle). Its "Write Once, Run Anywhere" principle, delivered through the Java Virtual Machine (JVM), means Java applications run consistently across Windows, Linux, and macOS without modification. That platform independence, combined with Java's static typing, strong tooling, and mature ecosystem, has made it the default language for enterprise software development for three decades.
Java 25 LTS, released September 16, 2025, is the current recommended production version. Java 26, released March 17, 2026, is a non-LTS feature release with only six months of support it is not for production workloads. Java 21 LTS (released September 2023) remains widely used in production and is still actively supported. Java 17 LTS is the minimum version required for Spring Boot 3.x and Spring Framework 6.x. Java 11 and Java 8 are still receiving long-term support from Oracle, but represent significant technical debt in any system that has not yet migrated.
The distinction between core Java and framework-level Java matters when hiring. A core Java developer understands the language fundamentals: OOP principles, the Collections API, concurrency and threading, the memory model, generics, streams, and the newer language features like records, sealed classes, and virtual threads introduced from Java 14 onwards. Framework-level Java development adds Spring Boot, Spring Security, Spring Data JPA, Spring Cloud, and Hibernate on top of those foundations. Most enterprise Java work requires both the core language knowledge to write correct, efficient code and the framework knowledge to use Spring's patterns correctly, rather than working against them.
Spring Boot 4.0 (supporting Java 25) and Spring Framework 7.0 (released November 2025) are the current production releases. Spring Framework 6.2.x open source support ends in June 2026.
Our Java developers and Java development teams build:
2+ Experience Years
Implements clearly specified features within an existing Spring Boot or core Java codebase under senior oversight. Understands core Java fundamentals, basic Spring Boot patterns, JPA repository queries, and unit testing with JUnit and Mockito. Works cleanly within an established project structure on well-defined tasks. Not suited for architecture decisions, performance investigations, or core Java design work without close guidance.
5+ Experience Years
Owns complete Spring Boot features independently from JPA entity design through to REST controller and test coverage. Proficient in Spring Security, Hibernate query optimisation, Maven or Gradle build management, Docker containerisation, and REST API design conventions. Makes sound decisions about service layer design, exception handling strategy, and database query efficiency. Works independently on mid-complexity Java web developer projects and integration work.
7+ Experience Years
Architects Spring Boot applications and microservices for long-term production stability. Deep knowledge of the Spring ecosystem (Boot, Security, Data, Cloud), JVM performance and garbage collection tuning, distributed system patterns, Kafka or RabbitMQ message queuing, Docker and Kubernetes deployment, and the testing strategy required to keep a large Java codebase reliable. Makes the technical decisions that determine whether a Java application scales cleanly or requires costly rearchitecting eighteen months after launch.
5+ Experience Years
Specialist in the core Java language rather than primarily in frameworks. These developers understand Java concurrency and threading in depth, the Collections framework, generic type system, stream processing, JVM memory model, and the newer language features: records, sealed classes, pattern matching, and virtual threads from Project Loom. Best suited for high-performance backend components, libraries, batch processing systems, and performance-critical application logic where framework abstraction is deliberately avoided.
5+ Experience Years
A Java developer assigned consistently to your application on a retainer basis, building institutional knowledge of the codebase rather than approaching each piece of work as an isolated task. The dedicated model makes most sense for Java applications with an ongoing development backlog: enterprise systems that need consistent feature development, a live Java web application requiring regular enhancements, or a Java backend serving a React or Angular frontend.
4+ Mixed levels
An experienced Java developer who works as a consistent, committed resource on your project remotely, at UK working hours. For organisations that need a senior-level dedicated Java developer without the commitment of a permanent hire, this arrangement provides the same developer working on the same application consistently, with full accountability and transparent progress tracking. All code in version control, all deliverables documented.
Spring Boot makes it possible to get a Java API working quickly. Making that API maintainable, testable, secure, and performant at production scale requires discipline that a developer without enterprise Java experience does not apply by default. Our Java developers write layered, tested, documented Spring Boot applications from the start not clean-up projects that require rearchitecting before they can be extended.
Every Java developer on your project is based in the UK. Technical discussions, sprint reviews, architecture decisions, and production issues all get addressed within the working day. For enterprise Java systems where decisions have long-term architectural consequences, having your developer available to discuss them in real time not across a timezone gap genuinely matters.
Java 25 LTS (September 2025) and Java 21 LTS (September 2023) are the recommended production versions. Java 26 (March 2026) is a non-LTS release with six months of support not for production. Our developers work on supported LTS versions and advise honestly about version selection for new projects and version upgrade timelines for existing ones. Java 8 and Java 11 systems carry real maintenance and security risk and should be migrated.
Spring Boot 4.0 and Spring Framework 7.0 (November 2025) represent a significant evolution from earlier Spring generations. Our Java web developers work with the current Spring stack: Jakarta EE 11, Spring Security 6.x, Spring Data, Spring Cloud, and the move from javax to jakarta namespaces. That current-generation knowledge is the difference between a Spring Boot application that benefits from modern Java performance and one that is fighting a framework release cycle it has not kept up with.
Your application code, API design, business logic, and enterprise data remain private. Non-disclosure agreements are signed as standard on every Java development project, dedicated developer retainer, and remote dedicated Java developer arrangement. For agencies using our Java development team on client accounts, we operate entirely under your brand.
Some Java projects need a single dedicated Java developer on a monthly retainer. Others need a Java development team for a specific build phase: a new microservices platform, a Spring Boot API for a new product, or a legacy modernisation programme. We structure the engagement around what the project actually requires, not around a standard model.
From first contact to a Java developer or development team working on your project, the process is direct and starts with understanding what your Java application actually needs.
Tell us about the Java project or system. The type of work needed Spring Boot REST API, enterprise backend, microservices, legacy Java modernisation, or dedicated Java developer retainer the current state of any existing codebase, the Java version and Spring version in use, and the timeline. The more context you provide, the more accurately we can assess the right developer level and engagement model. We respond within one business day.
For projects involving an existing Java application, our developer reviews the current codebase before agreeing a final scope. This covers the Java version, Spring Boot or framework version, test coverage level, build tooling, database configuration, existing technical debt, and any known performance or stability issues. For new Java builds, we carry out a requirements discussion to define the architecture, data model, API contract, and integration points before committing to a development approach.
Based on your project Spring Boot API, enterprise backend, core Java application, microservices architecture, or dedicated remote Java developer retainer we identify the most suitable developer from our team. You find out who they are and can review their relevant experience before work starts. If you want to speak with the developer before committing, we arrange that conversation.
Java development work proceeds in clear, documented stages with a staging environment for review before anything reaches production. For dedicated Java developer retainers, the developer works from a maintained backlog with regular progress updates. For project-based Java work, each milestone is reviewed and approved before the next begins. All code is committed to version control throughout, with test coverage maintained and documentation updated alongside the code.
At the conclusion of a project phase, we produce technical documentation covering the Spring Boot application architecture, data model, API contracts, deployment configuration, and what a future Java developer needs to understand the codebase without a lengthy knowledge transfer. For ongoing engagements, the same dedicate Java developer continues as the technical lead. We also offer Java development retainers for systems needing consistent, knowledgeable ongoing maintenance and feature development.
KIWI Commerce redeveloped my entire website, exactly to my requirements. They worked exactly along with my timeframe and were fantastic to work with. I would highly recommend this company. Thank you Sam and the team!
Great response to tickets. We feel our website is in safe hands with Kiwi. Any issues are fixed very quickly. Great value for money. We have been working with Kiwi for a couple of years now and find them very helpful and easy to get along with. Would highly recommend.
Working with Kiwi Commerce has been a very smooth experience. Their team is responsive, knowledgeable, and always willing to go the extra mile. From development to ongoing support, everything is handled efficiently and with great attention to detail. Highly recommended.
We’ve been working with Kiwi Commerce for ongoing website improvements and support, and the experience has been consistently positive. They are proactive, easy to work with, and quick to respond whenever we need assistance. Great team and great service.
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Java is a strongly typed, platform-independent programming language running on the JVM (Java Virtual Machine). It is used primarily for enterprise backend systems, REST and GraphQL API development with Spring Boot, microservices architectures with Spring Cloud, Java web application development, batch processing and data pipeline work, and cloud-native applications deployed on AWS, GCP, or Azure using Docker and Kubernetes.
Java is the right technology choice when a system needs to be stable, correct, and maintained by multiple developers over many years. Its static typing catches errors at compile time rather than at runtime. Its mature ecosystem of frameworks, testing libraries, and tooling reduces the cost of quality. Its performance at scale the JVM is a highly optimised runtime with decades of production tuning makes it the correct choice for high-throughput transaction systems in banking, logistics, and enterprise commerce. It is not the fastest language for prototyping a new idea quickly, but that is not what Java is for.
Core Java refers to the Java language and standard library: OOP fundamentals, the Collections and Streams APIs, generics, concurrency and threading, the memory model, and the newer language features introduced from Java 14 onwards records, sealed classes, pattern matching, and virtual threads from Project Loom. A core Java developer builds applications using the language directly without a framework providing the structure.
Spring Boot is the most widely used Java framework for web application and API development. It builds on top of core Java and adds opinionated defaults for application configuration, dependency injection, REST API development, database integration via Spring Data JPA and Hibernate, security via Spring Security, and testing. Most enterprise Java web developer and Java app developer roles involve Spring Boot alongside core Java knowledge. When hiring, a developer who knows Spring Boot well but has shallow core Java knowledge will struggle on performance problems and complex design challenges. Both layers matter.
Java 25 LTS (released September 16, 2025) is the current recommended production version for new applications. Java 21 LTS (released September 2023) remains widely used in production and is actively supported. Java 17 LTS is the minimum version for Spring Boot 3.x and Spring Framework 6.x. Java 26 (released March 17, 2026) is a non-LTS feature release with only six months of support it is not appropriate for production workloads. Java 8 and Java 11 applications are carrying increasing technical risk: the ecosystem is moving forward without them, and both require migration planning. If your application is on Java 8 or 11, upgrading to Java 21 or Java 25 LTS should be treated as a priority task, not deferred.
Spring Boot 4.0 (supporting Java 25 LTS) and Spring Framework 7.0 (released November 2025) are the current production versions. Spring Boot 3.x requires Java 17 or later as a minimum. Spring Framework 6.2.x open source support ends in June 2026 teams on Spring 6.2.x should plan migration to Spring Framework 7.x. The Spring ecosystem has made the migration from javax to jakarta namespaces (completed during the Spring 5 to Spring 6 transition) a prerequisite for all current-generation Spring development.
Yes to both. For ongoing Java development needs on a specific application or system, we provide a dedicated Java developer on a monthly retainer. The same developer works on the codebase consistently, building the context needed to make good decisions at pace. For larger projects requiring multiple Java developers working as a coordinated team a microservices platform, a major Spring Boot API build, or a legacy Java modernisation programme we provide and coordinate Java development teams.
Yes. All of our Java developers are UK-based and work remotely as standard. Remote Java development works reliably with Git version control, a staging environment for testing before production deployments, agreed sprint or milestone structure for project-based work, and regular communication checkpoints. For dedicated remote Java developer arrangements, we agree the tooling, communication cadence, and delivery tracking process before work begins so that progress is always visible.
Yes. Legacy Java modernisation is one of the more complex things a Java developer can be asked to do well. It requires reading and genuinely understanding existing code before changing it not assuming the codebase is wrong just because it is old. Our senior Java developers assess legacy Java applications, document what is currently there, identify what is valuable versus what can be replaced, plan the migration to Java 17, 21, or 25 LTS in stages that preserve application behaviour, and add test coverage to validate that behaviour before and after the migration. For Spring Boot 2.x to Spring Boot 3.x or 4.x upgrades which require the javax to jakarta namespace migration we manage the full upgrade path including dependency compatibility resolution.
Our UK-based Java development team is ready to look at your project. Whether you need a dedicated Java developer on a monthly retainer, a remote dedicated Java developer for ongoing work, a Spring Boot development team for a new API or microservices build, or expert Java developers to modernise a legacy Java 8 or Java 11 system, get in touch today. We respond within one business day.
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