Java Development Services

PS3G provides Java development services for organizations that run, or are about to run, serious back-office and transaction systems on the JVM. That includes a founder whose product needs an API that will still be sane at scale, a growing company integrating an order system with its ERP and its carriers, and an IT director inside a larger organization with a Java application that has outlived the people who wrote it. We build new Java services with Spring Boot, extend and integrate the ones you have, and bring older Java systems onto a supported, testable platform. The engineering is scoped to your situation, not to a minimum project size.

Java Development Services: what we build and for whom

Java is the language most organizations reach for when a system has to process a lot of transactions, talk to many other systems and keep working for a decade. That is why it sits under core banking, logistics, insurance claims, telecom billing and most large ERP integrations. As a Java development company we see three kinds of work most often.

• New services. REST and event-driven services built with Spring Boot, usually behind an API gateway, with a relational database, a message broker and a proper test suite from day one.
• Integration. Connecting Java systems to SAP, Oracle applications, payment processors, EDI partners and message queues, with retries, idempotency and audit trails rather than hope.
• Modernization. Upgrading applications on old Java versions, Java EE application servers, Struts or early Spring to current Java and Spring Boot, often in steps and without a freeze on new features. The wider options are on our application modernization page.

Java is not the right answer for everything, and we say so. A content website, a small internal tool or a data-science workload will usually be faster to build in WordPress, .NET or Python. A team that already lives in the Microsoft ecosystem is often better served by our .NET development group than by introducing a second platform. We make that recommendation during the assessment, not after the invoice.

What the service covers

Java software development with PS3G covers the full lifecycle: architecture, build, test, deployment and maintenance. The table below lists the typical work and the tools we reach for by default. Every choice is open to discussion if your platform standards differ.

Type of work	What it looks like	Typical tools
API and microservice development	REST and gRPC services, OpenAPI contracts, authentication with OpenID Connect, rate limits, versioning	Spring Boot, Spring Security, Spring Data, Hibernate, OpenAPI, Keycloak or Entra ID
Event-driven and batch processing	Consumers and producers on a message broker, nightly jobs, file imports, reconciliation runs	Kafka, RabbitMQ, Azure Service Bus, Spring Batch, Quartz
Enterprise integration	Adapters to ERP, CRM, payment, EDI and partner APIs; transformation and routing; error handling with replay	Spring Integration, Apache Camel, JAXB and Jackson, SOAP and REST clients
Modernization and upgrades	Java version upgrades, application server to Spring Boot, dependency and security remediation, containerization	OpenRewrite, Maven or Gradle, Docker, Testcontainers
Cloud deployment	Containers on Kubernetes or a managed app platform, infrastructure as code, pipelines, observability	AKS, EKS or GKE, Terraform, GitHub Actions or Azure DevOps, OpenTelemetry
Quality and performance	Unit and integration tests, contract tests, load testing, JVM tuning, memory and GC analysis	JUnit, Mockito, Testcontainers, Gatling or JMeter, JFR

If you need engineers rather than a delivered project, the same people are available through our hire Java developers page, on a monthly basis inside your team.

How we work

Every Java application development engagement starts with a short assessment. For a new build, that means the domain, the integrations, the non-functional requirements (volume, latency, uptime, data residency) and the team that will own the code afterwards. For an existing system, it means reading the code, the build, the dependency tree and the deployment, then writing down what is risky and what is merely old.

1. Assessment and architecture. A written view of the target architecture: service boundaries, data ownership, messaging, authentication, deployment. We keep it to the decisions that are expensive to reverse.
2. Walking skeleton. One thin slice from API to database to pipeline to a running environment, so the build, tests, security scanning and deployment exist before the features do.
3. Iterative delivery. Two-week increments with a demo, a reviewed pull request for every change, and integration tests that run against real dependencies in containers rather than mocks of everything.
4. Hardening. Load tests at the volumes you expect, failure drills for the broker and the database, dependency and secret scanning, and a runbook.
5. Handover or run. Documentation and a knowledge-transfer period if your team takes over, or a maintenance agreement under defined SLAs if we keep running it.

Team and stack choices

A typical team is a lead engineer in the United States who owns the architecture and your weekly conversation, with Java engineers at our India delivery center for build capacity, plus a QA engineer from our testing center of excellence. We default to a current long-term-support Java release, Spring Boot, Maven or Gradle, PostgreSQL or SQL Server, and containers. If your standards say Quarkus, Jakarta EE on a specific application server, or Oracle, we work in those.

Ask for a fixed-scope quote for your Java service or upgrade.

Where this fits with the rest of your systems

Few organizations run only Java. The common pattern we see is a Java core for transactions and integration, a .NET or PHP line-of-business layer that grew up around it, a React or Angular front end and a growing number of cloud services. Our job is to make those parts cooperate, not to rewrite them into one language.

Because PS3G’s core engineering practice is .NET and the Microsoft stack, we are used to Java and .NET sharing a building. The two pair well: both support OpenID Connect for a single identity provider, both speak the same message brokers, and both deploy as containers on the same Kubernetes cluster. We have placed Java services behind ASP.NET Core front doors, consumed Java-published events from .NET workers, and moved shared reference data into an API that both sides call. The enterprise software development page describes how we handle that kind of multi-system estate.

Examples by organization size

The engineering is the same at any size; what changes is the engagement. These examples are typical shapes, not named clients.

• A founder with a first version. A fixed-scope Spring Boot API with authentication, a handful of domain services and a pipeline to one cloud environment, built so that a future hire can read it. Java outsourcing at this stage works when the scope is written down and the code lands in the founder’s own repository from the first week.
• A growing company replacing a vendor integration. A dedicated engineer or pair for several months, building adapters between an order system, an ERP and three carriers, with replayable error handling and a dashboard the operations team can read. The company’s own developers join the reviews and take over at the end.
• A department inside a larger organization. A modernization program for a Java EE application that runs a core process: an assessment, a staged upgrade of Java and Spring, extraction of the riskiest module into a service, containerization and a managed-services agreement afterwards. Work happens inside the organization’s security, change-control and procurement rules.

Engagement models

• Fixed-scope project: a defined deliverable and price for a new service, an integration or a scoped upgrade.
• Dedicated team or staff augmentation: Java engineers inside your team on a monthly basis, scaled up or down as the roadmap changes.
• Managed services: we run, patch, monitor and improve your Java systems under defined SLAs.
• Advisory: an architecture review, a modernization assessment or fractional technical leadership.

How we start: a first conversation, a short assessment, a written proposal.

Why PS3G for Java work

We have been building software for more than a decade from Wilmington, Delaware and our delivery center in India, with Microsoft-certified and open-source-certified engineers on the same teams. We build and run our own products, including our HIPAA-compliant EHR and telehealth platform, DocVilla, so we know what it costs to keep a system up for years, not just to ship it. Our testing center of excellence is part of every delivery team rather than a separate department you have to ask for.

Related services

• All services: the full list of what we build, test, run and advise on.
• Hire Java developers: engineers on a monthly basis inside your team.
• Enterprise software development: multi-system programs where Java is one of several platforms.
• Application modernization: options for aging Java, .NET and PHP systems.
• API development and integration: the contracts that connect Java to everything else.

Frequently asked questions

What is included in your Java development services?

Architecture, development, testing, deployment and maintenance of Java applications: new Spring Boot services and APIs, event-driven and batch processing, integrations with ERP, CRM and partner systems, search, and the upgrade of older Java applications. You can buy that as a fixed-scope project, as engineers inside your team, as a managed service or as an assessment.

Do you work with Spring Boot or other Java frameworks?

Spring Boot is our default for new services because of its ecosystem, tooling and hiring pool, and most of our spring boot development uses Spring Security, Spring Data and Spring Batch alongside it. We also work in Quarkus, Jakarta EE on application servers, and older Spring and Struts codebases that need upgrading. We follow your platform standards when you have them.

Can you modernize an old Java application without rewriting it?

Usually, yes. Most older Java systems can be moved to a current Java release and Spring Boot in stages: upgrade the build and dependencies, replace the application-server-specific pieces, add tests around the riskiest modules, containerize, then extract services where there is a real reason to. A full rewrite is the last option, and we tell you when it is the right one.

Is Java or .NET the better choice for my project?

If your team, your hosting and your existing systems lean Microsoft, .NET is usually the better fit, and we build in both. Java makes sense where you already have Java systems and skills, where a specific library or vendor SDK is Java-only, or where your hosting and operations standards are built around the JVM. We will recommend one in the assessment and explain why.

How does Java outsourcing work with PS3G?

A lead engineer in the United States owns the architecture and your weekly conversation; Java engineers at our India delivery center provide build capacity with overlapping hours; a QA engineer tests every increment. Code lives in your repositories, cloud accounts are in your name, and the agreement covers intellectual property, security and handover from the start.