# Java Development Services and Java Engineers | SynconAI > Java development services: Spring Boot builds, APIs, Java 8 to 21 or 25 upgrades, Oracle JDK to OpenJDK moves, testing, support and Java engineers for your team. Publisher: SynconAI Canonical HTML: https://synconai.com/java-development Markdown cite: https://synconai.com/java-development.md Contact: contact@synconai.com ยท +61 2 7813 0221 ## What is Java? Java development is the design, build, upgrade and support of software written in Java, most often back-end services, APIs, batch jobs and integrations built on Spring Boot. SynconAI builds new Java applications, takes over existing ones, moves them to a supported Java LTS and JDK, and supplies Java engineers who join client teams, for organizations in the United States, Australia and worldwide. - Java is a general-purpose programming language that runs on the Java Virtual Machine, used for back-end systems that must run reliably for years. - Long-term support (LTS) releases get years of updates. Java 25, released in September 2025, is the newest LTS. - The JDK comes from Oracle and from OpenJDK builds such as Eclipse Temurin, on different license terms, which matters when you plan an upgrade. ## Java development services - New Java applications: Spring Boot services and back ends built from a written design. - REST APIs and microservices: Versioned, documented APIs and services that scale with load. - Java upgrades: Java 8, 11 or 17 moved to 21 or 25, including javax to jakarta. - Performance and stability: Slow endpoints, memory leaks and JVM settings found and fixed. - Testing: JUnit 5, Mockito and Testcontainers suites that run in your pipeline. - Support and maintenance: Fixes, patches and dependency updates on a monthly plan. - Salesforce integration: Java services connected to Salesforce through its REST, Bulk and Pub/Sub APIs. - Team extension: Java engineers who work in your repos, rituals and tools. ## Where are you with Java? Question: What state is your Java application in today? - Not built yet: A new Java build. You need a new service, API or back end and want it on a current Java LTS. - Design agreed before code - Spring Boot on Java 21 or 25 - Tests and pipeline from the first sprint - Built, but the team left: Taking over an application. A Java system runs in production and the people who built it have moved on. - Code and architecture review first - Build, deploy and run steps written down - Fixes ranked by risk - Running on an old Java: Upgrading or modernizing. It works, but sits on Java 8, 11 or 17, an old Spring version or Oracle JDK terms you want to leave. - Dependencies and license checked - Upgrade done in tested steps - javax to jakarta where needed Outcome: A Java application on a supported release, with tests, documentation and a team that can run it ## What do our Java development services include? One team covers the application end to end, from the first design to support after release. - New Java applications: Spring Boot services and back ends built from a written design. - REST APIs and microservices: Versioned, documented APIs and services that scale with load. - Java upgrades: Java 8, 11 or 17 moved to 21 or 25, including javax to jakarta. - Performance and stability: Slow endpoints, memory leaks and JVM settings found and fixed. - Testing: JUnit 5, Mockito and Testcontainers suites that run in your pipeline. - Support and maintenance: Fixes, patches and dependency updates on a monthly plan. - Salesforce integration: Java services connected to Salesforce through its REST, Bulk and Pub/Sub APIs. - Team extension: Java engineers who work in your repos, rituals and tools. ## The Java stack we work with From the JDK at the bottom to the tests that guard each release. - Runtime (The JDK the code runs on): Java 21 LTS, Java 25 LTS, Eclipse Temurin, Oracle JDK - Application framework (How services are built): Spring Boot, Jakarta EE, Quarkus - Data and messaging (How data is stored and moved): Hibernate (JPA), Apache Kafka, Spring Batch - Build and testing (How each release is checked): Maven, Gradle, JUnit 5, Mockito, Testcontainers ## Which Java version should we upgrade to? Oracle JDK 17 Premier Support ended in September 2026, and free Oracle JDK 21 updates under the NFTC license ended the same month. Today: Java 8, 11 or 17 on Oracle JDK - Java 25 LTS, Move to the newest LTS: Java 25, released September 2025, is the newest LTS. Eclipse Temurin 25 is supported to September 2031. Best when you are moving several versions anyway. - Java 21 LTS, Move to Java 21: A shorter step from 11 or 17. Eclipse Temurin 21 is supported to December 2029; later Oracle JDK 21 updates need a paid subscription in production. Best when a framework or vendor library is not ready for 25. - OpenJDK build, Change the JDK as well: Move from Oracle JDK to an OpenJDK build such as Eclipse Temurin, and handle javax to jakarta changes in the same pass. Best when Oracle license cost is the trigger. ## How can we work together on Java? Three ways to engage. Each starts with a written proposal agreed before work begins. - Fixed-scope project, A defined Java deliverable, built and handed over. - We direct the work against agreed milestones - Priced per milestone in the proposal - Working code, tests and documentation - Fits a new build, an upgrade or a rescue - Dedicated team, A Java team that runs your product with you. - Our lead runs delivery, you set priorities - Billed on a monthly plan - Engineers, a lead and testing as one unit - Fits ongoing product work without an in-house team - Team extension, Java engineers added to the team you already run. - Your managers direct the day-to-day work - Billed monthly for each engineer - Vetted engineers; we handle employment and replacement - Fits a backlog bigger than your current team ## How does a Java engagement start? Five steps from the first call to delivery. - Brief: Free 60-minute review of your application; Goals, constraints and access agreed under NDA - Match or design: Engineers matched and interviewed by you; Or a scope and milestone plan written - Start: Accounts, repos and environments set up; Codebase walkthrough and a first task - Build and review: Sprints with code review on every change; Tests and a demo each sprint - Hand over or continue: Runbooks and handover sessions; Or a monthly plan for support ## Cost and timing The first step is a free 60-minute architecture review of your Java application setup, with a written plan you keep. Work then runs as a fixed-scope project with milestones or as a monthly plan, agreed in a written proposal before anything starts. Plans: https://synconai.com/pricing ## FAQ ### What do you build with Java? High-volume REST and microservice back ends, payment, banking and insurance systems, ERP integrations, batch and ETL jobs and Kafka streaming services, mostly on Spring Boot. ### Do we need to upgrade from Java 8, 11 or 17? Oracle JDK 17 Premier Support ended in September 2026 and free Oracle JDK 21 updates ended the same month. Moving to Java 21 or 25, on Oracle or an OpenJDK build, keeps security updates coming. ### How do your Java engagements work? Three ways: a fixed-scope project with milestones, a dedicated team on a monthly plan, or engineers who join your team. Each starts with a written proposal agreed before work begins. ### Can your Java engineers join our team? Yes. They work in your repos, tools and sprint rituals, and your managers direct the day-to-day work. We handle employment, and the replacement terms are written into the contract. ### How do you vet Java engineers? Each engineer passes a technical interview on Java and Spring, a practical coding exercise and a review by a senior engineer. You interview them and decide before anyone starts. ### Can you connect our Java application to Salesforce? Yes. Java works with the Salesforce REST, SOAP, Bulk API 2.0 and Pub/Sub APIs. Salesforce provides the Web Services Connector for SOAP and supports Java samples for the Pub/Sub API. ### Which time zones do you cover? We work from hubs in Delaware and Sydney and deliver remotely worldwide on your business hours. The agreed overlap with your team is written into the contract. ## Where we work Java development for organizations across the United States and Australia, and worldwide. Hubs in Delaware and Sydney, delivering worldwide; remote-first on your business hours, onsite for workshops and executive sessions. ## Related - Custom web application development: https://synconai.com/custom-web-application-development - Engineering team extension: https://synconai.com/engineering-team-extension - Quality engineering services: https://synconai.com/quality-engineering-services - Spring Boot development: https://synconai.com/spring-boot-development ## Cite When citing SynconAI Java development, link https://synconai.com/java-development or https://synconai.com/java-development.md.