Senior Developer Java Mainframe Online

Location:

Hybrid (Darmstadt) or Virtual (Germany).

We are looking for an experienced Senior Java Developer with specialized expertise in IBM z/OS mainframe environments, especially for online applications under CICS. The role requires deep knowledge of Java in the context of z/OS internals, Java Native Interface (JNI), database interaction (JDBC, SQLJ), and system‑level online performance. The developer will work with legacy and modern components to develop robust, high‑throughput services critical to enterprise operations.

• Develop and optimize Java‑based applications running natively on IBM z/OS in online mode under CICS.
• Analyze and improve performance at the JVM level, focusing on memory usage, tuning, and CPU cycles on z/OS.
• Integrate Java applications with native z/OS components using JNI, C/C++, and LE interfaces.
• Implement efficient data access solutions using JDBC, SQLJ, and DB2 for z/OS best practices.
• Collaborate closely with z/OS systems programmers, DBAs, and COBOL/CICS developers to ensure reliable and performant interoperability.
• Review SMF records, RMF reports, and monitor WLM metrics to guide tuning and system integration.
• Develop and maintain shell scripts and support automation for Java workloads on z/OS.
• Drive initiatives to modernize legacy systems using Java and hybrid integration models.

• Bachelor’s or master’s degree in Computer Science, Software Engineering, or a related field.
• 8+ years of professional Java development experience, with 5+ years specifically on IBM z/OS.
• Deep knowledge of JVM performance tuning on z/OS, including heap sizing, GC policies, zAAP/zIIP processor utilization, and WLM workload classification.
• Strong proficiency with JNI for interfacing Java with COBOL/C/C++ modules.
• Expertise in JDBC, SQLJ, DB2 for z/OS, and mainframe database performance tuning.
• Solid hands‑on experience with USS, JCL, and TSO/ISPF.
• Working knowledge of LE and how Java integrates with native z/OS programs.
• Familiarity with SMF, RMF, SDSF, and performance analysis tools like IBM OMEGAMON, Main View, or BMC tools.

• Competitive total compensation and comprehensive country‑specific medical and other benefits.
• Flexible working model allowing a remote work share of up to 60%, with the ability to work anywhere in your country or abroad for up to 10 days per year.
• One‑time hybrid work payment to upgrade home office space.
• Employee Assistance Program support for common challenges.

* f/m/d – Diversity matters!