LLM.coPrivate, self-hosted LLM deployments
Legal AI infrastructure for firms
AI RFP discovery and response drafting
Automatic.coBusiness process automation
Secure AI virtual data rooms10 business days
To start a Java engagement
Scoping through first sprint
100%
Senior engineers, US-based
No offshore handoff
Every sprint
Working software on a preview URL
Not a status deck between milestones
100%
Code and infrastructure you own
From the first commit
Where Java fits
What a Java engagement is actually building
Java's reputation as an "enterprise language" undersells how much of the modern stack still runs on it. Here's where it actually shows up.
Enterprise backends and APIs
Spring Boot is the default today for a Java service — dependency injection, an embedded server, and a huge ecosystem of production-tested libraries for security, data access, and messaging, all with sane defaults instead of the XML configuration files older Java frameworks were known for.
Financial and transactional systems
Strong static typing and a mature ecosystem of tooling for correctness — from the compiler through static analysis to a deep testing culture — make Java a common choice anywhere a bug has a direct financial or compliance cost, which is a meaningful share of why it's still standard in banking and insurance.
Big data infrastructure
Hadoop, Spark, and Kafka are all JVM-based at their core, even when a data team primarily writes Python or Scala against them. Java or Kotlin engineering is frequently needed at the infrastructure layer underneath a data platform, not just at the application layer on top of it.
Android (legacy, and still real)
Kotlin is Google's preferred language for new Android development now, but a large amount of production Android code is still Java, and a huge share of Android engagements are extending or maintaining that code rather than starting fresh in Kotlin.
Internal enterprise tooling
Line-of-business applications, integration middleware, and internal APIs that need to interoperate with a decade of other enterprise Java systems — where compatibility with what already exists matters more than using this year's framework.
High-throughput services
The JVM's just-in-time compiler and decades of garbage-collector tuning work make it a genuinely strong choice for services that need to sustain high request volume with predictable latency, once that tuning work is done correctly.
Decisions that matter
The version and architecture decisions that decide whether a Java system is maintainable
Java's stability is a strength and also why so many production systems are years behind current — the language rarely forces an upgrade, so nothing does, until a library or a security requirement finally does.
Which LTS release you're actually building on
Java ships a new version every six months now, but most production systems track the Long-Term Support releases — 8, 11, 17, and 21 — because those get years of security patches instead of a few months. A huge share of enterprise Java is still on 8, which is increasingly hard to hire for and missing a decade of language and JVM improvements.
Spring Boot as the default, not the only option
Spring Boot covers the overwhelming majority of new Java backend work well. Quarkus and Micronaut exist for cases that specifically need fast startup and a small memory footprint — serverless functions and container-dense environments — where Spring Boot's flexibility costs more than it's worth.
Virtual threads changed the concurrency conversation
Java 21's virtual threads (Project Loom) let a service handle huge numbers of concurrent blocking operations — database calls, HTTP requests — without the memory cost of one OS thread per request, which used to be Java's real ceiling under load. A lot of the reactive-programming complexity teams adopted to work around that ceiling is no longer necessary on current Java.
Maven vs. Gradle
Maven's rigid, XML-based convention is still the safer default for a large team or a codebase with many contributors, because there's exactly one way to configure a build. Gradle's more flexible, code-based configuration is faster for large multi-module builds and increasingly common in newer projects — the choice matters more for build speed and team habits than for the finished application.
The module system, and why some upgrades stall on it
The module system introduced in Java 9 restricts reflection-based access that a surprising amount of older enterprise code — and older libraries — relied on informally. It's one of the most common reasons a Java 8-to-current upgrade takes longer than the version number difference suggests.
Garbage collector choice
The default collector handles most workloads fine, but a service with strict latency requirements benefits from evaluating G1, ZGC, or Shenandoah deliberately rather than accepting whatever the JVM defaults to — this is a tuning decision worth making explicitly on anything latency-sensitive, not an afterthought.
What's involved
Java engagement types
The scope driver here is usually the age of what already exists — a greenfield Spring Boot service is a different project than an upgrade to a Java 8 monolith with a decade of accumulated dependencies.
| Engagement | Commitment | Timeline | What's included |
|---|---|---|---|
| Codebase and dependency audit | Fixed scope | 1 – 3 weeks | A review of JVM version, framework, dependency health, and test coverage, with a prioritized upgrade or build plan. |
| New Spring Boot service | Fixed scope | 6 – 12 weeks | A backend service or API built on current-LTS Java and Spring Boot, including data access, security, and a test suite. |
| Java 8/11 → 17/21 upgrade | Fixed scope | 6 – 16 weeks | Dependency and module-system remediation, GC and performance re-tuning, and regression testing against the existing behavior. |
| Monolith-to-services decomposition | Fixed scope | 10 – 20 weeks | Extracting a bounded piece of a large Java application into an independently deployable service, without a big-bang rewrite. |
| Dedicated Java engineer | Staff augmentation | Ongoing | A senior Java engineer embedded in your existing team, working your sprint cadence and your codebase. |
Ranges assume US-based senior engineers. The audit is the cheapest way to find out how much of an upgrade is mechanical dependency work versus genuinely difficult module-system or library-replacement work.
Right tool, wrong tool
When Java is the right call — and when it isn't
Java's ecosystem depth is a real advantage for the systems it was built for, and unnecessary ceremony for the ones it wasn't.
Right call: long-lived enterprise systems
Strong typing, a mature testing culture, and backward-compatibility guarantees make Java a genuinely good bet for a system that has to keep running correctly for a decade with a rotating team of maintainers, which describes most large enterprise backends.
Right call: high-throughput services under real load
The JVM's performance characteristics under sustained load, once tuned, hold up well against most alternatives — this is a big part of why it's still the default in banking, insurance, and large-scale data infrastructure.
Wrong call: quick internal scripts and prototypes
Java's ceremony — classes, build files, a compile step — is real overhead for a one-off script or a fast prototype. Python or a shell script gets there faster with less code to maintain afterward for something genuinely disposable.
Wrong call: greenfield AI/ML prototyping
The machine learning ecosystem — libraries, tutorials, hiring pool — concentrates overwhelmingly around Python. Java has a role at the infrastructure layer under a data platform, but building a new model from scratch in Java means giving up most of that tooling for no real benefit.
Depends: new mobile development
Kotlin is Google's recommended language for new Android apps and interoperates with existing Java code, so a new Android project today usually starts in Kotlin rather than Java — but a team already fluent in Java, maintaining a large existing Java Android codebase, has a legitimate reason to keep extending it in Java.
Depends: team background and hiring market
Java's hiring pool is large but increasingly concentrated around current versions and Spring Boot; a codebase stuck on Java 8 and an older framework is measurably harder to hire for than the same system on 17 or 21, which is itself an argument for the upgrade beyond the technical case.
Migration and integration
Where a Java engagement is really an upgrade or an integration
A large share of Java work isn't a greenfield build — it's bringing an existing system forward, or connecting it to something newer.
The Java 8 upgrade backlog
Java 8 is by far the most common version still in production across enterprise Java, years past its last public update. The upgrade path to a current LTS is rarely a single jump — module-system compatibility, deprecated or removed APIs, and third-party library versions all need to be verified, which is why an audit is worth doing before committing to a timeline.
Framework-era migrations
Older Java systems built on Struts, JSF, or hand-rolled Servlet-based architectures are frequently still running in production. Moving that logic to Spring Boot is a well-worn path, but it's a genuine re-architecture, not a find-and-replace, and it's usually done incrementally rather than as one cutover.
Monolith decomposition
Splitting a large Java application into services is worth doing when a specific part of it needs to scale or deploy independently from the rest — not as a default modernization step. The honest first move is usually extracting the single highest-value bounded piece and proving the pattern before committing the rest of the codebase to it.
Integrating with newer systems
A mature Java backend frequently needs to talk to newer infrastructure — a modern message broker, a cloud-native data platform, an API gateway — that didn't exist when the original system was designed. That's usually an integration project, not a rewrite, and treating it as one avoids a much larger and riskier undertaking than the actual requirement calls for.
Hiring a Java developer
What actually matters when you're hiring
"Ten years of Java" is a weak signal on its own — a developer can spend a decade on Java 8 and Struts and never touch the language's modern features.
Current-version fluency, not just years
Ask whether a candidate has actually worked with the module system, virtual threads, or records and sealed classes — features that changed how idiomatic Java looks — rather than taking years of experience as a proxy for staying current.
Spring ecosystem depth
Spring Boot fluency is close to table stakes now; what separates a strong hire is understanding what Spring's auto-configuration is actually doing, not just using the annotations that make it work by default.
JVM literacy
A developer who can read a heap dump or explain what a GC pause is doing to your latency is a different level of hire than one who's only ever worked at the application-code layer. This matters most for anything with real throughput or latency requirements.
Testing culture
JUnit usage that includes integration tests against a real (or realistically mocked) database and messaging layer, not just unit tests around pure functions, is a strong signal for how a codebase will hold up under a growing team.
Related
Related services
What Java builds usually connect to.
Questions
Common questions about Java development
What teams ask before a first call.
Day to day, mostly extending and maintaining existing enterprise systems: adding features to a Spring Boot service, fixing a defect in business logic that has real financial or compliance stakes, writing the tests that keep a large codebase safe to change, and reviewing how a change affects performance under load.
On a modernization engagement, that shifts toward version upgrades, dependency remediation, and carefully extracting pieces of a monolith without breaking what already works.
It depends on whether you need a dedicated engineer added to an existing team, a new Spring Boot service built from scratch, or a Java 8 upgrade on a codebase with years of accumulated dependencies — that last category varies the most, since the real cost is discovered during the audit, not estimated from a feature list.
A scoping conversation, ideally alongside a short audit for anything involving an existing codebase, gets you a real number faster than a generic range would.
Almost always yes, eventually — Java 8 is years past broad vendor support and the hiring pool for it keeps shrinking. How disruptive the upgrade is depends entirely on what's in the codebase: dependency versions, use of reflection the module system now restricts, and any library that was never updated for newer Java.
An audit before committing to a timeline is the difference between an accurate estimate and a guess — some Java 8 codebases upgrade cleanly in a few weeks, and others surface a genuinely hard problem that was always going to need fixing eventually.
Kotlin is Google's recommended language for new Android development and interoperates directly with existing Java code, so most new Android projects start there today. A large amount of production Android code is still Java, though, and extending an existing Java Android codebase in Java is frequently the right call rather than a forced rewrite into Kotlin.
For a system that needs to run reliably for years, handle real throughput, and be maintainable by a team that will change over time, yes — Spring Boot on a current LTS Java version is a genuinely strong, well-supported default, not a legacy choice. It's the wrong call for a fast prototype or for work that leans heavily on the Python-centric AI/ML ecosystem.
Despite the similar name, they're unrelated languages. Java is a statically typed, compiled-to-bytecode language that runs on the JVM and is common in backend and enterprise systems. JavaScript is dynamically typed and runs natively in browsers, with Node.js extending it to the backend. The name overlap is a historical marketing decision from the 1990s, not a technical relationship.
Yes — this is a common starting point. The first step is the audit: JVM version, framework, dependency health, and test coverage, so you know what you're actually inheriting before committing to a roadmap, rather than discovering the state of the codebase through the first few production incidents.
You do. Source code lives in a repository under your organization from the first commit, and any cloud infrastructure runs in your own account. That's the only arrangement that doesn't lock a long-lived enterprise system to a single vendor for its next upgrade or its next hire.