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BigTree108

Java development services

Java development services for banking, fintech and insurance platforms, e-commerce and marketplace back ends, enterprise and SaaS systems, Spring Boot microservices, Kafka integrations and the modernisation of older Java applications, with dedicated Java developers for your team or a Java project delivered end to end.

What we build with Java

  • Spring Boot microservices and APIs

    REST, gRPC and GraphQL services on Spring Boot 4 and Java 25 LTS, with virtual threads for work that waits on I/O, records for the data on the wire, and Spring Security with OAuth 2.0 and OpenID Connect. Quarkus or Micronaut where the project already runs on them.

  • Banking, payments and insurance systems

    Payment, ledger, lending, trading and policy administration services with idempotent transactions, double-entry records and a full audit trail, exchanging ISO 20022 messages and built to the controls that PCI DSS and open banking rules ask for.

  • E-commerce and marketplace back ends

    Catalogue, pricing, inventory, order and checkout services that hold up under sale-day traffic, with Redis caching, search on Elasticsearch or OpenSearch, and events between services on Kafka.

  • Enterprise and SaaS platforms

    Multi-tenant SaaS products, ERP and CRM extensions and workflow systems, with single sign-on through Microsoft Entra ID, Okta or Keycloak and role checks on every endpoint rather than in the browser.

  • Event streaming and integration

    Kafka, RabbitMQ and Apache Camel integrations between Java systems and the rest of the estate, with Spring Cloud Stream, schema-registry contracts, idempotent consumers, retries and dead-letter topics.

  • Batch jobs and data access

    Spring Batch reconciliations, settlements and reports over PostgreSQL, Oracle or SQL Server through JPA and Hibernate or jOOQ, with schema changes as versioned Flyway or Liquibase migrations that run in the pipeline.

  • Modernising legacy Java

    Java 8 and 11, Java EE and old Spring applications moved to current Java and Spring Boot step by step, with OpenRewrite making the mechanical changes such as javax to jakarta and the test suite growing ahead of each change.

  • Cloud-native Java on Kubernetes

    Containers on Kubernetes, AWS, Azure or Google Cloud, built by a pipeline that scans dependencies, with GraalVM native images or CRaC where start-up time matters, and traces, metrics and logs through OpenTelemetry.

  • Full-stack Java applications

    Spring Boot back ends with Angular, React or Vue front ends generated from the OpenAPI contract, or Vaadin and Thymeleaf interfaces for internal tools that stay in one language.

Hire Java developers

  • Dedicated Java developers

    Java developers who join your team full time, work in your repositories, tracker and meetings, and report to your lead. You interview them; we carry the Ukrainian contract, payroll, invoicing and leave.

  • Java project delivery

    A team that takes the Java project from scope to release: estimate, build, tests and deployment, with a technical lead on our side who owns the plan and the quality.

  • Java support and take-overs

    An existing Java system taken over from another team or kept running: a read-only review and a written list of risks first, then fixes and new features in order of impact.

The dedicated team page explains how specialists join your team, and the outsourcing page covers project delivery, take-overs and how we charge.

Who works on your Java project

  • Java engineers

    Spring Boot services, Kafka and legacy modernisation

  • Software architects

    Service boundaries, data ownership and the way off a monolith

  • Front-end engineers

    Angular, React or Vue in front of the Java services

  • Cloud and DevOps engineers

    Kubernetes, pipelines and observability

  • QA engineers

    Manual testing and automated suites

How we work on Java

Tests ship with the feature, the build ends with zero warnings, dependencies stay on current releases and a security advisory is an unconditional upgrade, and configuration is validated at startup rather than discovered in production.

Developers work in your repositories, your tracker and your process. The Ukrainian contract, payroll, invoicing and leave stay with us, and everything they write is assigned to you.

Other languages we work in

Programming languages overview

Questions about Java development

Which industries do your Java developers work in?

Banking, fintech and insurance, where they build payment, lending, trading and policy systems and core banking integrations; e-commerce and marketplaces (catalogues, orders and pricing); enterprise software and SaaS (ERP, CRM and workflow products); healthcare (patient records, claims and HL7 FHIR integrations); and telecom (billing, provisioning and network management).

Which Java versions and frameworks do you work in?

Java 25 and 21 LTS with Spring Boot for services, Quarkus or Micronaut where a project already uses them, JPA, Hibernate or jOOQ for data, and Kafka or RabbitMQ for messaging. Code on Java 8 or old Spring is moved forward step by step rather than rewritten, with tests added ahead of each change.

Do you have Java engineers on the team?

Yes. Java engineers build back-end services on our team under the same engineering rules as every other practice: tests with every feature, zero warnings, current dependencies and secrets kept only in a key vault.

Can you take over an existing Java system?

Yes. A take-over starts with a read-only review and a written list of risks before anything changes, then fixes in order of production impact. You see the list before you commit to anything beyond the review.

How quickly can Java developers start?

When the right Java developer is available, the start is gated only by your interview and the NDA and IP assignment. Otherwise we run a search, which typically produces candidate profiles within two to three weeks, and nobody starts until you have said yes.

How do we hire Java developers through BigTree108?

Tell us the work, the seniority and the hours you need. We propose one or two people with their profiles, you interview them the way you would interview your own hire, and you sign one agreement with BIG TREE 108 LLC and receive one invoice a month.

Who owns the work they produce?

You do. Every specialist has a signed contract with BigTree108 that assigns all work product to the company, and our agreement with you assigns it onward. Code, designs and documents are delivered into your own repositories and tools, not kept where only we can change them.

Need Java developers?

Tell us the system, the Java and Spring versions and the hours you need. You get an answer within one business day: candidate profiles or a plan for the work.

Email hello@bigtree108.com How we respond