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Freelance Java Developer

The greatest option for creating high-performance software is without a doubt Java. Java is used to create safe, scalable, and quick software. By collaborating with our dedicated Java development team, you can develop apps that stand out for their efficiency. For more than ten years, our Java developers have been developing applications capable of processing huge amounts of data in a short time (one million queries per second!).

The Financial Times and Deloitte have named Stratoflow as one of the fastest growing custom Java development companies in Europe. As a close-knit group of top-notch Java engineers, we maintain long-term collaborations built on trust and excellent communication.

Ready to boost your business with high-performance software? Transform your ideas into reality with Stratoflow’s Java developers.  Contact us today to learn more!


 Let’s connect!

java web development company


years on the market


top notch Java developers

1 billion

transactions per hour in our finance system

Stratoflow was instrumental in the completion of several projects of Tier 2. Other than developments, they also handled the technical support and maintenance of the applications. The team has been reliable, flexible and has displayed excellent technical capabilities in the workplace.

java web development services
Andrew Kennedy
Founder & Director, Tier 2 Consulting

Java Development Services

Java Web Applications

Modern web applications based on Java backend.

Custom Java Application Development

Bespoke digital solutions tailored to your business.

Enterprise Applications

Complex data processing systems.

Java SaaS Application Development

We build and extend SaaS applications for B2B and B2C.

Java Product Development Service

We create high-performance custom Java products based on modern architecture.

Cloud-based Java Application Development

Our systems are deployed in Amazon AWS, Azure, Google Cloud, Hetzner, Linode, and many others.

Dedicated Java Teams

We extend your development teams with experienced Java developers.

Java Consulting and Technical Due Dilligence

Comprehensive system design, technology and source code audits in M&A processes and internal reviews.

Modernization of Existing Java Solutions

Upgrade your existing Java solutions to modern standars in an incremental model.

Java Maintenance and Support Services

Extend and support your current Java systems.

Java Migrations

We offer migrations of any legacy application to Java.

Java Integrations

Integration and data exchange systems based on MuleSoft, Apache Camel and Red Hat Fuse.

Why You Need Java Developers

Freelance Java Developer

Java is a timeless and long-lasting technology. This mature yet constantly evolving  programming language serves to develop software for desktops computers, enterprise servers, mobile devices as well as web browsers.

How is Java applied in software development? You can build everything: from ordinary web-based applications to advanced back-end systems, data processing engines and games, and various highly-scalable software solutions.

Java is an object-oriented programming language which makes complex problems easier to solve providing greater modularity. Java objects allow for the code to be reused, which simplifies testing as well as troubleshooting. But these are only a few of Java advantages.

There are many reasons to hire Java developers. We present the key ones:

The popularity of Java

Java is one of the most popular programming languages in the world. According to Statista, Java is currently the fifth most-used programming language globally. It has strong support from the programming community, and numerous tools, frameworks, and libraries, making it an attractive choice for many companies. Market demand, in turn, influences the desire for development and upskilling among dedicated Java developers and professionals. For employers, this means one thing – the opportunity to hire highly specialized talent ready to add value to their business.

Versatility of use

Java is operating system independent, meaning that code written in Java can run on various platforms, such as Windows, macOS, Linux, and mobile devices. It is also used in many fields, such as enterprise applications, servers, mobile and web applications,, games, embedded systems, etc. So by choosing Java and hiring Java developers, companies can scale their business quickly.

Security of digital products coded in Java

Java has built-in security mechanisms, such as memory management, sandbox mechanisms, file access management, and multithreading, which help create secure applications. For this reason, the language is often used in projects requiring high security, such as financial systems and medical apps. By hiring a dedicated Java developer, companies gain confidence that they are choosing a robust solution that will allow them to quickly achieve their business goals without risking the loss of valuable data and reputation.


Java is known for its ability to handle large and complex projects. It has a rich tools and framework ecosystem that allows applications to scale quickly. It is essential for companies that plan to develop their products in the future. By hiring top Java developers, who know how to leverage this programming language with experience scaling digital products, companies gain confidence that their business will grow steadily and in line with market demand.

A mature community

A huge programming community around the Java programming language is eager to share knowledge and experience. Thus, you can easily find the right talents and verify their skills when hiring Java developers.

Knowledge of other languages

Java developers often have experience in other programming languages, which can be helpful for projects that require knowledge of different technologies. Such a versatile pool of programming skills eliminates the problem of project downtime and speeds up the delivery of the finished product to the market.

High productivity

Java is a language with extensive syntax, which allows for writing readable and modular code. This makes Java developers more productive, which is vital for companies that rely on efficient web development, project management, and quick delivery.


Development costs with Java are significantly lower compared to other technologies. The reason is related to the time spent developing the software. What is more, applications written in Java are easier and cheaper to maintain.


Java, as a compiled language, is known for its efficiency as it compiles all the code at once. This prevents delays of execution time. Consequently, the use of energy is lower, which makes Java an environmentally friendly option. Nowadays, choosing energy efficient languages that can significantly minimize energy consumption is crucial.

Below you can see a comparison of the efficiency of the languages: Java, C, and Python.


Elapsed Time (seconds)


Based on these results, C is 2.34 times slower than Java and Python is 33.34 times slower than Java (source).

Low latency applications

Business applications are in high demand these days. As a result, software developers continuously strive to create low latency systems with reaction times measured in microseconds. For this reason, if you choose Java, the problem of latency disappears.

Java Developers For Your Industry

For the past 20 years, our experts have been assisting companies from a wide range of industries in the process of digital transformation. We have delivered end-to-end custom software solutions that have brought our clients’ businesses to a higher level.


We have been involved in the fintech industry since the very beginning of our activity. We’ve managed to build a system processing more than 1 billion transactions per hour. Due to our great experience in the field of finance technology, you can be sure that your project will be in good hands. Our top-notch Java developers build financial systems of outstanding technical capabilities and support our customers during their entire technical journey.

By introducing cloud-based innovative architecture, the finance software we build in Java is secure, highly scalable, and able to process a massive amount of data in a very short time!

So, if you care about energy-efficient software development for your financial application – you’ve come to the right place!


The newest technological solutions have already become an indispensable part of the travel industry. We provide our clients with an advanced infrastructure which improves the scalability and performance of their travel platforms.

Using our expertise, we offer end-to-end services for travel search engines capable of handling 300 million queries daily and returning results in real-time.

The future of travel technology is here with us!


Our ecommerce software development services are dedicated to modern retail businesses of any size. We implement solutions tailored to your clients’ needs by leveraging the latest Java technologies that will accelerate and grow your ecommerce.

Understanding the operations and priorities that drive your ecommerce is our main focus when designing efficient, scalable and high-performance software.

We’ve had it tested – come see for yourself!


Let us enhance, upgrade and accelerate your healthcare IT solutions with our high-performance software. In Stratoflow, we are primarily guided by a thorough understanding of the complexity of your issue.

We do an in-depth analysis and select the best technologies that the healthcare industry needs, and do our best to guide you through the entire process.

Healthcare industry requires the newest technology. Let’s bring it in together.

Our Technology Stack

Web applications

Mobile-friendly, responsive interfaces (Angular, VueJS, Bootstrap)


Scalable in-memory processing systems (Hazelcast, Grid Gain, Oracle Coherence, ultrafast JVM solutions)


Modern, lightweight Java development with Spring Boot, Grail, Kotlin


PostgreSQL, Oracle Database, MySQL, ElasticSearch, Redis


MuleSoft, Apache Camel / Red Hat Fuse


Complete functional and non-functional testing coverage automated within the CI build process (Cucumber, JUnit, Selenium, JMeter)

Message queues

Scalable architecture for heavy load processing Apache Kafka, RabbitMQ, ActiveMQ


Amazon AWS, Google Cloud, Microsoft Azure, dedicated hosting solutions

Project management

Agile development process with Jira, Slack, ClickUp

Stratoflow successfully customized the system according to the specific functionalities and without bugs reported. The team was commended for their adaptability in the work process and for their responsiveness.

destination management company
Joshua Blavins
Tech PM, Konekt Group

Our process

How We Deliver

Iterative approach with short feedback cycles and seamless communication is the key factor of success.



Step 1

Our clients are located around the globe but we always try to start with a planning visit to learn more about the project details and build team rapport.



Step 2

We work together on ballpark estimates and task priorities to build a roadmap maximizing business value.



Step 3

We work in short development cycles with daily communication between developers and clients to make sure we end up with the best result.



Step 4

Demonstration of the current progress enables to review the interim results.



Step 5

Iterative approach is the best way to adjust the scope and direction.



Step 6

We are your partner in a complete software development lifecycle, starting from analysis through development and testing, to data migrations, installation and maintenance.

Why Choose Us?

Our cooperation model


  • Complete projects or staff augmentation (working as part of your technical team).
  • On-site or remote model with daily IM/video meetings.
  • Mixed on-site/remote.
  • Consulting: PoC, system architecture design, architecture & code reviews.
  • We do not subcontract further to other companies, project teams are constructed from our direct employees.

The way we communicate


  • We value transparency, collaboration, and honesty.
  • Daily communication via e-mail/IM/video with our team of Java developers in Poland.
  • Source code stored daily in a code repository owned by the client.
  • Each sprint ends with deployment to the UAT environment, live demo and testing.
  • Once testing is complete, the UAT version is promoted to production.
  • A Technical Lead / Delivery Manager is assigned to work with the client as the main point of contact.
  • Nearshore office location in Poland.

We believe in our values


When building high-performance systems, the following values always guide us.

  • Craftsmanship – making sure that the solutions we create satisfy both the client and our engineering spirit.
  • Collaboration – a spirit of cooperation and understanding the fact that only by working as a team we are able to create something worthwhile.
  • Transparency – sharing information, being open to giving and receiving constructive feedback.
  • Responsibility – a sense of responsibility for our work, a proactive approach.

Why we are the best custom software development company for you


  • Successful and long-term cooperations with clients from the UK, the US and Europe.
  • Solid track record of delivering complex B2B and B2C systems.
  • Highly specialized software development company with organic growth and great employee retention.
  • Strong engineering spirit with a truly agile approach.
  • Recognized by Financial Times and Deloitte as the fastest growing software development company.
  • Our experts have 20 years hands-on experience building advanced systems for finance, travel, health, and technology sectors.
developers at the office

What Our Clients Say

The features implemented have received overwhelmingly positive feedback from end-users. Stratoflow has an incredible technical expertise and a high degree of flexibility when it comes to changing project requirements.

fintech application development
Adam Hill
Chief Technology Officer, Legerity

Stratoflow successfully completed numerous web-based projects. They can handle technical challenges very well. The team has exceptionally talented developers with a strong grasp of business objectives and proactively provided solutions.

travel management company
Arnd Jan Prause
Chief Operating Officer, musQueteer

The bespoke metal exchange platform works great, it is easily accessible and richly functional. Stratoflow managed deadlines capably, meticulously documented their progress, and delivered a complex project at an affordable cost.

destination management company
Bartlomiej Knichnicki
Vice Chairman, Supervisory Board, Mennica Skarbowa


Why Java?

Java is one of the most widespread programming languages in the world. The versatility of its application mainly influences this situation. The slogan “write once, run anywhere” has been with us constantly since 1995, so it’s unsurprising that the profession of Java Developer is valued in the job market.

People with Java programming skills, along with experience and knowledge related to the Java ecosystem, such as frameworks, tools, or databases, are sought after by employers. It also has a large programming community and versatile applications in various projects.

Therefore, hiring experienced Java developers can bring many benefits to businesses in multiple industries, both in terms of functionality and reliability of the developed Java software development itself.

How do you hire a Java developer?

1. Defining the requirements: Before starting the hiring process, it is essential to determine the requirements for the Java developer position carefully. This includes aspects such as experience level, technical skills, preferred frameworks or tools, as well as communication skills or understanding of the company’s industry.

2. Selecting the employment form: If you know exactly what tasks a Java programmer is expected to perform, consider whether it will be a full-time or part-time job. Also, refine the forms of employment – employment contract or outsourcing.

3. Job advertisement: Next, it’s a good idea to post a job ad on relevant recruitment platforms, the company’s website, or specialized groups for Java developers. The ad should be well-written, detail the requirements and benefits offered, and encourage potential candidates to apply.

4. Interviews: Selected candidates should be invited to an interview, which can be conducted in person or online. During the interview, it is a good idea to focus on assessing technical skills, experience, problem-solving, teamwork approach, and communication.

5. Final Decision: After all the stages of recruitment have been completed, a final decision should be made on hiring a Java developer. In doing so, it is worth considering the candidate’s experience, hard and soft skills, references, and fit with the form of employment and the projects planned to be completed.

How much does it cost to hire a Java developer?

Java developers’ pay rates can vary depending on a number of factors. Knowledge and experience, location, and market conditions are key.

Data published by Upwork shows that:

  • A beginner or freelance Java developer earns an average of $25 per hour,
  • An intermediate Java programmer can make $49 per hour,
  • A senior Java developer receives an average salary of $160 per hour.

What does this look like in terms of localization?

java developers salaries


Skills to Look for in a Java Developer

1. Knowledge of tools

A Java developer should have excellent knowledge of Java capabilities, including syntax, data types, operators, exception handling, threads, and collections. They should also be familiar with the latest versions of Java and be able to use new features in practice.

Familiarity with popular Java frameworks like Spring, Hibernate, and JavaFX is also essential. These frameworks enable the development of advanced Java applications, such as web, enterprise, and desktop applications.

2. Databases

Knowledge of basic database concepts, such as SQL, and experience working with relational databases such as MySQL, Oracle, or PostgreSQL is also a critical competency for a Java developer.

3. Software testing

Knowledge of testing tools and techniques is essential for Java developers. After all, the code they create needs to be readable and reliable.

4. Troubleshooting and debugging

The ability of software engineers to troubleshoot and debug Java code is essential in software development. A Java developer should be able to identify and resolve code bugs and diagnose and resolve performance or security issues.

5. Communication and teamwork

Communicating and working with other team members is vital for a Java developer, especially if working on a team project. The ability to share knowledge, give and receive feedback, problem solving skills, and communicate effectively with other team members can speed up software development.

6. Independence and self-discipline of software engineer

Java developers should be independent, disciplined, and able to manage time effectively when writing code and working on other tasks. Planning, organizing work, and learning and improving skills independently is important in a dynamic IT environment.

These are just some essential skills to look for in a Java developer. In addition, evaluating technical and soft skills such as communication, self-reliance, and teamwork in the hiring process is vital.

What are the main features of Java?

The key feature of Java is a proven track record of being a technology foundation for large, mission-critical systems. 

What makes Java a fantastic choice for building a long-lasting application is the following:

  • a possibility to build and develop your system locally and then run it on servers of any size and architecture;
  • the high-performance execution of JVM;
  • static type checking;
  • great selection of modern and mature frameworks.

How to hire remote Java developers? Our tips

More and more developers value and even expect high independence and the ability to work remotely from home or anywhere. Companies, too, have changed their approach, influenced by the pandemic. Today, skills and aptitude matter more than the workplace.

If you want to hire a Java developer, then:

  1. Define the precise requirements for the Java developer position and job description, such as experience level, technical skills, preferred tools, or programming languages related to the project.
  2. Develop a compelling recruitment ad that accurately describes the expectations for candidates and the benefits offered.
  3. Verify candidates based on their resumes and cover letters, assessing their compliance with the requirements specified in the ad. Conduct technical tests, such as programming tests or hands-on tasks, to evaluate candidates’ programming skills. In remote meetings, you can also conduct interactive coding sessions (coding interviews).
  4. Check candidates’ references to confirm their work experience and skills.
  5. Verify the competencies of selected candidates against project needs. Consider time and cultural differences if the selected Java developer lives in a country far from yours.
  6. Once you have selected the best candidate, prepare a contract on a remote employment basis. Ensure the agreement contains all the necessary information, such as salary, responsibilities, deadlines, working hours, and time accounting rules.
  7. Finally, take care of the onboarding process for the newly hired Java developer, which may include familiarization with the tools, work environment, project, and company organization. Also, provide regular communication and manage the work of remote Java developers to monitor the project’s progress, resolve any problems, and maintain effective cooperation.

Java Experts - high performance tools

How to outsource Java development?

A single developer or a larger team? Do you need an expert in a specific area of Java programming, or are you thinking more about an outside programming department? Do you want to outsource projects temporarily or permanently? Are you interested in candidates for Java programmers from close locations (nearshore outsourcing), or can they be from further away (offshore outsourcing)?

These are key questions to ask yourself if you want to outsource your Java development services. Where to find good Java developers?

Among the best ways to look for Java developers are:

  • recruiting outsourced to specialized agencies,
  • using custom software development companies to hire Java programmers,
  • looking for Java talent on social media channels – such as LinkedIn,
  • finding Java developers on forums like Quora or Facebook groups,
  • using the X-Ray search engine,
  • networking at tech events,
  • using employee platforms,
  • finding top software developers through open-source projects.

Searching for top Java web development talent is not a simple task, but it is worth the time. If you want to know more about finding software developers in 2023, check out our tips, which we described in a separate article.

Countries with the best Java developers

The specialists you need may have more expertise in other countries than the one where your company is located. For example, the choice of such a collaboration may be based on a ranking created by Hackerrank, which rated 50 countries based on which one has the best developers.

hire java developers - countries

Instead, the comparison chart developed by a team from Bridge indicates the following countries from Eastern Europe, Central Europe, and Latin America:

  1. Poland

  • Talent pool – 295,000+
  • EF English Proficiency Index – 597
  • Tech skills level – competitive to cutting-edge
  • Best for – Java, Python, and C++ development process
  1. Ukraine

  • Talent pool – 192,000+
  • EF English Proficiency Index – 525
  • Tech skills level – cutting-edge
  • Best for – Java, Python, and C++ development
  1. Mexico

  • Talent pool – 223,000+
  • EF English Proficiency Index – 436
  • Tech skills level – lagging to competitive
  • Best for – Java, Python, and C++ development
  • Argentina

  • Talent pool – 114,000+
  • EF English Proficiency Index – 556
  • Tech skills level – lagging to competitive
  • Best for – Java and Python development.

Are Java developers in demand?

If you’re wondering if Java developers are still in demand, the answer is one – yes! The role of a Java developer is increasingly being described as the profession of the future. With the rapid development of the new technology sector and rapid digitization, knowledge of Java offers many career opportunities – to engage in exciting projects, bringing a stable source of income.

Java, a programming language that has been on the market for almost 30 years, continues to develop well. It is worth noting that over 90% of Fortune 500-listed companies use Java in their projects. Additionally, according to the TIOBE index, Java is considered the most popular programming language in the world.

Given these facts, developing a career as a Java developer is a very sensible choice. Java software development constantly evolves, allowing it to adapt to technological advances and market trends. Furthermore, its vast applications in web and mobile application development and modern technologies such as big data, IoT, blockchain, and artificial intelligence (AI) make Java an even more attractive choice for many companies.

How to build a low latency Java system?

A design of a low latency Java system needs to follow similar principles as a high-performance architecture. We also need to remember that the key is to minimize our response/processing time per request. Reactive programming would become a handy processing model here. In this way, we are able to decouple unit operations and execute them as asynchronously as possible to minimize the response time and maximize the resource usage. Spring WebFlux available in Spring Boot Framework or Akka are mature Java frameworks that will help you introduce reactive programming models to your applications.

Is Java suitable for machine learning and artificial intelligence applications?

Yes, although Python is probably the best choice for prototyping due to large availability of different AI/ML algorithm implementations you may try. However, the numerical computation code in Java is at least 20-30 times faster compared with a direct implementation in Python. This results in a 20 times cheaper and smaller system that needs to be run in your production environment.

Is Java still a good option for software development?

Yes, Java programming language is a fantastic option for software development due to its security, high-performance, mature set of proven frameworks and libraries, well-defined standards and a large global talent pool.

How can I keep track of my Java development process?

We strongly believe in extensive communication and transparency as the best options to mitigate project risks. This is why we apply an agile approach to all our projects (see our values: About Us). You may learn more about our development process here: How We Work. 

Can I expect support after the project ends?

Yes, we provide maintenance and extension support for Java applications of any kind. We have implemented many Java projects serving various industries, such as ecommerce, travel, fintech, and healthcare.

Why should I choose Java technology?

Java programming language is one of the most popular choice of modern companies who care about high-performance solutions. Starting a custom Java development project with us means a close collaboration with dedicated Java developers. As an experienced Java development company, Stratoflow follows an agile software development process. Read more: How is Java Used in Software Development: The Ultimate Guide.

Learn More

Consult your project

Submit the form to discuss your project and our software development, team augmentation and consultancy services. Our clients are located in the US, the UK, and Western Europe.

or call us: +1 415 340 8020 (US) or +44 20 3322 8684 (UK)


What happens next?

  1. Initial Request
    When you submit your request, we will immediately confirm it and analyze your initial questions and project scope.
  2. Discovery Call
    We schedule a call at a convenient time to discuss your project requirements and goals, and answer any questions you may have.
  3. Expert Meeting
    This meeting focuses on detailed project analysis, strategy development, and technology selection.
  4. Proposal
    Based on the insights gained from our discussions, we will prepare a commercial proposal that includes the scope of work, timeline, and cost estimates.
  5. Contract
    The final step is to sign a contract that defines the terms of our relationship and the framework for successful project delivery.
Arkadiusz Drysch | CTO