Java Development Company for Mission-Critical Systems

Java is both a programming language and a platform, in Oracle’s own description: source code is compiled into bytecode that runs on the Java Virtual Machine, so the same application can run on Microsoft Windows, Linux or Mac OS. This section explains that platform, groups the nine Java development services above by what they change, and sets out how the work runs, what lands on your side of the table, which engagement model suits which project, what moves the cost, and what to ask any custom Java application development company, including us.

On this page

• What Java is, and why the same application runs on several systems
• Custom Java software development services, grouped by what they change
• How a Java build runs, step by step
• What lands on your side of the table
• Dedicated team, fixed price or time and materials: which suits your project
• What moves the cost of Java development
• How to compare Java development companies
• Java development questions, answered
• More about Java development
• Talk to our engineers

What Java is, and why the same application runs on several systems

Oracle’s own account runs like this. Source code is written in plain text files ending in .java. The javac compiler turns those files into .class files, which contain bytecodes, the machine language of the Java Virtual Machine, rather than code native to your processor. The java launcher then runs the application on an instance of the Java Virtual Machine.

That mechanism is what this page means when it says Java applications run seamlessly across environments supported by the Java Virtual Machine. Oracle’s Java Virtual Machine Specification calls the JVM the cornerstone of the Java platform and the component responsible for its hardware and operating system independence, and OpenJDK describes itself as the place to collaborate on an open-source implementation of the Java Platform.

Oracle also publishes how long it supports each release. It provides Long-Term-Support on specific releases and names Java SE 8, 11, 17, 21 and 25 as LTS releases on its Java SE Support Roadmap, with Java 29 the next planned LTS release, in September 2027. The same roadmap lists Premier Support until September 2028 or later for Java SE 21, and until September 2030 or later for Java SE 25.

Custom Java software development services, grouped by what they change

The nine services above fall into three kinds of work. Every line below uses the service’s own wording from this page.

The technologies the upgrade service names, in their stewards’ words

This page describes the upgrade as moving legacy Java systems built on outdated JSP and Servlets to modern Spring and Spring Boot frameworks, to improve maintainability, performance and compatibility while extending the lifecycle of critical enterprise applications.

How a Java build runs, step by step

The five steps are this page’s own Java development methodology, shortened.

1. Assessment of requirementsBusiness objectives, technical requirements and success metrics, turned into a clear scope and a structured roadmap.
2. Agreement on service modelDedicated team, fixed price, or time and material, chosen on complexity, timelines and engagement needs.
3. Design and developmentArchitects and developers turn the requirements into a Java solution, iteratively.
4. Testing and quality assuranceFunctional, performance, security and integration testing, with client feedback loops.
5. Deployment and supportGo-live, then monitoring, issue resolution, maintenance and enhancements.

The cadence under every step is the one published on our about page: two week sprints, so working software arrives every two weeks, and a first production release typically lands in three to six months.

What lands on your side of the table

The six items below are published on our software development services page, and none of them is specific to one language.

• The repository and the cloud accounts, in your name from the first commit.
• A written scope and a costed roadmap, before any build starts.
• Working software every two weeks, not a status report about software.
• Architecture and a security posture you can put in front of a reviewer.
• Infrastructure your own engineers can run once we hand it over.
• Monitoring, maintenance and a roadmap after launch, priced up front.

Dedicated team, fixed price or time and materials: which suits your project

This page’s methodology names these three service models. How each is priced, where it fits and where it goes wrong are restated from our software development services and custom software development pages.

Before you outsource Java development under any of the three, settle the commercial terms in writing: a ceiling on spend, the notice period, who owns the repository, what happens to the cloud accounts, and what counts as done. They are cheap to agree at the start and expensive to negotiate once you are dependent.

What moves the cost of Java development

Two published figures sit under every engagement model, both on our about page. The drivers under them carry no number, because a number without your scope attached to it is decoration.

• How settled the scope is. A settled scope can be quoted as a fixed price. An unsettled one priced as though it were settled is where the buffer, and the argument, comes from.
• The seniority and mix of the team. This is the stated reason the rate band has a range at all.
• The integration count, and whether the other side is documented. An integration into a modern documented API is routine. An integration into an undocumented system that somebody has to reverse engineer is a project of its own.
• The non functional requirements. Availability targets, performance under load, and how deep a security review the system has to survive are architecture decisions with a cost, not adjectives.
• Data migration. Reconciling the data, proving it moved correctly, and deciding what to do with the records that do not fit the new model.
• What happens after launch. Get deployment and maintenance priced up front, rather than sold back afterwards.

How to compare Java development companies

Whichever Java development software company you shortlist, including this one, these questions separate the claim from the practice. The first two come from Oracle’s own release policy; the rest are published on our software development and custom software development pages for any vendor, and they work the same way on any Java app development firm.

• Ask which Java SE release the system will run on. Then check it against Oracle’s support roadmap, which names the long-term-support releases and their Premier Support dates.
• Ask what happens to a non-LTS release. Oracle treats any previous non-LTS release as superseded once a new feature release is made available.
• Ask what they have integrated with, by name and version. Experience with a platform and a completed integration against it are different claims.
• Ask what happens when the estimate is wrong. The answer tells you how the relationship will actually work.
• Ask who reviews the code, and whether that person can veto a merge.
• On testing, ask specifically what is automated and what is manual.
• Ask what documentation is a contractual deliverable, not what they promise to write.
• Ask which certifications are audited and which are self declared, then ask for the report date. Our about page lists what Sthenos does not hold, including a SOC 2 report and an ISO 27001 certificate.

Java development questions, answered

Can we hire Java developers rather than commission a whole project?

Yes. This page’s methodology names a dedicated team as one of three service models, beside fixed price and time and material. On our software development services page a dedicated team is priced monthly, per named engineer, for continuous product work over quarters. If you already have the plan and the management and need hands, team augmentation adds engineers into your existing team.

What is the Java Virtual Machine?

Oracle’s specification calls it the cornerstone of the Java platform, the component responsible for its hardware and operating system independence. It is an abstract computing machine with its own instruction set, and compiled Java code reaches it as bytecode in .class files, which is why the same application can run on several operating systems.

Which Java releases have long-term support?

Oracle names Java SE 8, 11, 17, 21 and 25 as Long-Term-Support releases on its Java SE Support Roadmap, and intends to make future LTS releases every two years, with Java 29 planned for September 2027. A non-LTS release is considered superseded once the next feature release is made available.

Can a JSP and Servlet application be moved to Spring Boot?

That is the upgrade legacy system service on this page: legacy Java systems built on JSP and Servlets are upgraded to Spring and Spring Boot, which the page says improves maintainability, performance and compatibility. In Jakarta EE’s words, a Jakarta Pages template is compiled into a Jakarta Servlet; Spring Boot, in the Spring project’s words, makes it easy to create stand-alone, production-grade Spring based applications.

How much does Java development cost?

Sthenos rates are $150 to $250 per hour, depending on the seniority and mix of the team, and a typical project runs $50,000 to $200,000. Where the scope is clear we quote a fixed price for a defined outcome, with a costed roadmap before any build starts.

Who owns the code you write?

You do, entirely, from the first commit. The repository and the cloud accounts are in your name, with no licence back to us and no dependency on us continuing to exist.

How long does a Java project take?

Sthenos works in two week sprints, so working software arrives every two weeks and a first production release typically lands in three to six months. A date more precise than that comes out of discovery, because it depends on scope rather than on goodwill.

More about Java development

Services. Custom software development, software development services, enterprise software development, SaaS development services, cloud migration and optimization, team augmentation, software outsourcing services.

Standards and documentation, at the source. Oracle, About the Java Technology, the Java Virtual Machine Specification, the Java SE Support Roadmap, OpenJDK, Jakarta Servlet, Jakarta Pages, Spring Framework, Spring Boot.

Checklists, costs and related languages. The production readiness checklist, the production readiness audit, what custom software costs, and the .NET, Python, PHP and Node.js development pages.

Ready to talk? Tell us which Java release your system runs on, what it has to integrate with and which of the three engagement models you are leaning towards, and we will tell you which parts of the work are known and which are discovery. Talk to our engineers.