Senior Java Software Engineer

Senior Core Java Engineer – Core Java 21 – Data Integration Platform – Remote (NL) [95K] Are you a core Java developer who knows their way around complex, high-performance codebases without leaning on Spring Boot? And do you like the idea of working on a platform that connects business systems for over 2,000 customers worldwide? Keywords: Java 21, Core Java, Netty, Jetty, JPA, PostgreSQL, Concurrency, Multithreading, Monolith My client builds a data integration platform that powers supply chains through real-time integration, automation, and intelligent data processing. Think connecting cloud and on-premise systems at scale, for thousands of customers globally. The codebase is a Java 21 monolith. No microservices, no Spring Boot. Instead, the team has built homegrown frameworks on top of Netty, Jetty, and JPA. If you're someone who actually understands what's happening under the hood, you'll feel right at home here. You'll be designing, building, and maintaining production-grade backend software, contributing to technical design and code reviews, and taking full ownership of features from implementation through to production. Your profile: 5+ years of backend Java developmentStrong Core Java skills — comfortable without Spring BootExperience with concurrency and multithreadingFamiliar with JUnit, Mockito, or similar testing frameworksExperience with relational or NoSQL databases (PostgreSQL, Oracle, MySQL, SQL Server, MongoDB) Bonus if you have experience in one of these areas: Networking: Netty, Java NIO, sockets, TCP/IP, HTTP/HTTPS, gRPC, Vert.xDistributed systems: Kafka, AMQP, MQTT, REST, WebSocketPlatform engineering: high availability, load balancing, connection pooling, failover, performance optimizationAI-focused engineering The offer: Up to 95K annuallyFully remote within the NetherlandsEtc. :-) Interested? Reach out to me at j.dits@doghouse.nl