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Hire Java Developers for Backends Built to Scale

Bring on Java and Spring Boot engineers who design microservices, integrate core systems and keep transactional workloads reliable under real traffic.

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Java engineers for serious backend workloads

Java remains a dependable choice for banking platforms, logistics systems, telecom backends and large commerce engines. Spring Boot, mature tooling and a predictable runtime make it suitable for code that must run for years. What these systems need are developers who understand transactions, concurrency and integration, not just syntax. Without that depth, small mistakes surface as outages later.

Our Java developers work with product companies scaling a backend, enterprises maintaining critical services, and teams breaking a monolith into services. Common tasks include new Spring Boot services, Kafka consumers, batch jobs, API gateways, performance tuning and moving older Java EE applications to a modern setup on containers. Some clients need one senior engineer, while others need a small backend squad.

We match engineers to your architecture, whether that is a modular monolith, microservices on Kubernetes or a mix. They work inside your sprint cadence, follow your coding standards and write unit and integration tests with JUnit and Testcontainers. Nexzem stays responsible for contracts, continuity and replacements, so your architects can concentrate on design.

Build a team with Java Developers

Pick roles and seniority, choose what they will work on, then send the brief. We come back with matching profiles.

Java Developers, by seniority
  • Junior Java Developer
    0
  • Mid-level Java Developer
    1
  • Senior Java Developer
    1
Round out the team
  • .NET Developer
    0
  • Golang Developer
    0
What they will work on

What our Java Developers can do for you

Java and Spring Boot engineers for microservices, enterprise backends, integrations and high-traffic transactional systems.

  1. 01

    Spring Boot microservices

    Independently deployable services with Spring Boot, Spring Data and Spring Security, including service discovery, configuration management and observability from the start.

  2. 02

    Event-driven systems

    Kafka or RabbitMQ producers and consumers with idempotent processing, dead-letter handling and schema evolution, so events are never silently lost.

  3. 03

    Enterprise integrations

    Connections to ERPs, payment processors, core banking or warehouse systems via REST, SOAP, SFTP or message queues, with retries and reconciliation reports.

  4. 04

    Monolith decomposition

    Identifying service boundaries, extracting modules gradually with the strangler pattern and keeping data consistent while old and new code run side by side.

  5. 05

    Batch and scheduled processing

    Spring Batch jobs for settlements, imports, billing runs and report generation, with restartable steps and clear logs for operations teams.

  6. 06

    JVM performance tuning

    Profiling, garbage collection tuning, connection pool sizing and query fixes that reduce latency and infrastructure cost for heavy Java workloads.

  7. 07

    Java EE modernisation

    Moving older Java EE or Struts applications to Spring Boot and containers, upgrading JDK versions and replacing unsupported libraries step by step.

Why hire Java Developers through Nexzem

  • Screened for backend fundamentals

    Interviews cover concurrency, transactions, JPA pitfalls and Spring internals, so you get engineers who understand what the framework does underneath.

  • Evaluate before committing

    A short trial on your services shows how the developer handles your codebase, tests and review feedback in practice.

  • Real-time collaboration

    An agreed daily overlap keeps design discussions, code reviews and production incident calls inside shared working hours.

  • IP and access under your control

    NDA on request, your repositories and environments, and full ownership of every service and library written for you.

  • Continuity for critical systems

    We keep documentation current and provide a replacement with a handover if a developer leaves, protecting systems your business depends on.

  • Capacity that flexes

    Bring in extra Java engineers for a migration or peak release and reduce afterwards, with monthly per-developer billing.

How to vet a Java developer

Java experience varies enormously, from maintaining Java 8 monoliths to building cloud-native Spring Boot services on current releases. Check fluency in modern Java features such as records, streams, pattern matching and virtual threads, and depth in Spring Boot, Spring Data and Spring Security. Strong developers can explain how dependency injection, transactions and connection pools behave rather than treating the framework as magic.

Database skills are critical, since most Java performance problems start there. Ask how candidates diagnosed slow JPA queries, handled lazy loading, designed indexes and managed migrations with Flyway or Liquibase. For distributed systems, look for experience with messaging such as Kafka, idempotent processing and observability with metrics and traces.

Architecture judgment matters as much as coding. Ask when a candidate would split a system into services and when a modular monolith is wiser; our microservices vs monolith comparison covers the trade-offs. Developers who default to microservices for every project often create more problems than they solve.

  • Fluent in modern Java and Spring Boot.
  • Strong SQL and JPA performance skills.
  • Experience with messaging and idempotent processing.
  • Writes tests with JUnit and Testcontainers.
  • Understands JVM tuning in containers.
  • Has upgraded applications from older Java versions.
  • Documents designs clearly for architects and auditors.

Interview questions we use for Java developers

Our questions focus on the problems Java developers face in enterprise systems: transactions, performance, concurrency and long-term maintainability. Candidates explain real decisions, review short code samples and reason through scenarios such as a slow endpoint or a message processed twice in a payment flow.

Good answers show how candidates verify assumptions with profiling, logs and tests before changing code. We also value developers who can explain technical choices clearly to architects, auditors and business stakeholders, which is common in banking, insurance and other regulated sectors where Java dominates.

  • How do you detect and fix the N+1 query problem in JPA?
  • What happens when a transactional method calls another method in the same class?
  • When would you use virtual threads, and what should you watch out for?
  • How do you make a Kafka consumer safe against duplicate messages?
  • How would you upgrade a Spring Boot application from Java 8?
  • How do you size JVM memory for a service running in a container?

In-house vs dedicated Java developer

Enterprises usually have in-house Java teams responsible for core systems, and they add dedicated developers for modernization programs, integrations or temporary peaks. Dedicated developers who have worked on several enterprise systems bring patterns for upgrades, testing and observability that internal teams can adopt, while internal staff retain domain knowledge and long-term ownership.

For organizations considering a language shift, our Kotlin vs Java comparison explains how the two coexist on the JVM. Our Java development services cover full modernization programs when more than individual developers are needed. Dedicated developers can also mentor internal staff on newer Java features and practices.

Hiring Java Developers: from first call to first commit

Every stage has an owner and an exit, so you always know where your hire stands.

  1. Stage 1

    Map your architecture

    We discuss your services, JDK version, messaging, databases and deployment platform.

  2. Stage 2

    Propose Java engineers

    You get profiles with matching experience in Spring, Kafka, batch processing or legacy migration.

  3. Stage 3

    Technical evaluation

    Interview candidates on design and code, or ask for a system design discussion with your architect.

  4. Stage 4

    Trial in your sprint

    The developer onboards to your environments and works on planned stories during the trial.

  5. Stage 5

    Long-term engagement

    Continue monthly, plan team changes with us and keep knowledge documented for continuity.

Where Java Developers make a difference

  • Modernizing a Java 8 monolith

    An enterprise running a large Java 8 application adds developers who add tests, upgrade to a current long-term support release and Spring Boot version, and restructure code into modules ready for gradual extraction.

  • Integration layer for core systems

    A bank or insurer exposes core systems through Spring Boot APIs with security, transformation and audit logging, letting new mobile and partner channels connect without modifying fragile legacy platforms underneath.

  • Event-driven processing with Kafka

    A company processing orders or transactions at volume builds Java consumers on Kafka with idempotent handling, retries and dead-letter queues, so every event is processed exactly as intended even during failures.

  • Performance tuning a slow service

    A Java service with rising latency gets a developer who profiles it with Java Flight Recorder, fixes inefficient queries and connection pool settings, tunes memory for containers and verifies improvements with load tests.

Tools our Java Developers work with

Proven, well-supported tools chosen for your scale, budget and team, never for novelty.

  • Java
  • Spring Boot
  • Kafka
  • PostgreSQL
  • Redis
  • Docker
  • Kubernetes
  • AWS

Developers who work alongside Java Developers

All 46 developer roles

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Hiring Java Developers: FAQs

Something else on your mind? Ask a consultant and get a reply within one business day.

What affects the cost of hiring a Java developer?

Seniority, depth in Spring, Kafka or cloud platforms, required overlap and engagement length. We bill monthly per developer with a short trial, and confirm the figure after a free consultation.

Can your Java developers work on legacy code?

Yes. Many have upgraded JDK versions, replaced unsupported libraries and moved Java EE or Struts applications to Spring Boot without disrupting users.

Do they handle DevOps tasks as well?

Most are comfortable with Docker, CI pipelines and Kubernetes manifests. If you need a dedicated DevOps engineer alongside them, we can add one.

How do you protect our systems and data?

Developers work in your environments with access you grant and revoke. We sign NDAs on request and all code and IP belongs to you.

Can we interview the developer ourselves?

Always. You run the interviews, set any exercise you like and make the final decision on who joins your team.

Can your Java developers work within our bank's security rules?

Yes. Developers work through your approved access methods, follow your secure coding standards, change management and audit requirements, and cooperate with security reviews. We agree data handling and access restrictions upfront, so everything aligns with your internal policies.

Do your Java developers use Kotlin as well?

Some do. Many Java developers on our team also write Kotlin, which interoperates fully with Java on the same JVM. If your organization is introducing Kotlin, they can write new modules in Kotlin while maintaining existing Java code.

We work with clients across the USA, UK, Australia, UAE, New Zealand and India.

Where we work

Tell us who you need on your team.

Share the role, stack and start date. We reply within one business day with matching profiles and next steps.

Book a free consultation+91-7302622997