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Java on z Systems Delivers Portability, Security and Other Benefits

As people expect quick, secure transactions available any time, anywhere, modernization and innovation on the mainframe are necessary to meet these needs. Java* is at the heart of such transformation. An IDC study, “The Business Value of the Connected Mainframe for Digital Transformation” (, places Java at the center of both modernization and innovation on the IBM z Systems* platform.

Designed to be portable and platform-agnostic, Java enables the mainframe to participate in a modern ecosystem by allowing skills and innovation from across the broader IT organization and industry to leverage z Systems servers. As one of the most popular programming languages, Java has become a staple for the enterprise, enabling developers to bring to market complex, scalable and robust applications with speed and agility, notes Marcel Mitran, IBM Distinguished Engineer and CTO of LinuxONE*.

“Java on z means clients now have a choice in how they want to address business problems. … Java means clients have the freedom to solve business problems with the tools they think are best and most appropriate.”

—Marcel Mitran, IBM Distinguished Engineer and CTO of LinuxONE

In addition to platform portability, Java also features built-in security, threading and safety. “Java packs a lot capabilities in a single language and runtime environment,” Mitran says. “It also has a proven history of being an enterprise-ready language.”

The language’s strengths are two-fold:

  1. It’s portable both as a platform-agnostic runtime and as an open standard. “This allows clients to do fit-for-purpose placement of work while also guaranteeing their investments in IT assets will be protected strategically,” Mitran cites.
  2. Java’s maturity—with two decades of built-in, proven security and scalability, and a seasoned skills pool—makes it a trusted and robust environment for mission-critical workloads

Integration Importance

Java is well integrated into the z Systems platform. Traditional transaction processing and data-serving environments (e.g., CICS*, IMS*, DB2* and WebSphere*) have long enabled business logic written in Java for batch and online transaction processing. Many next-generation workloads in the cognitive, analytics and cloud spaces (e.g., Apache Spark, IBM Operation Decision Manager, IBM Machine Learning for z/OS*, IBM zAware, IBM z/OS Connect and z/OS Management Facility) are written in Java. These workloads depend inherently on Java’s built-in security, safety and portability.

Mainframe clients are taking advantage of Java to modernize their environments. In a survey of 95 z Systems clients conducted in 2016, 68 percent now have Java on IBM z* in production. Of those, more than 80 percent described the project as successful or very successful.

“Java allows clients to enjoy the qualities-of-service of the z Systems platform while leveraging broadly available skills to develop applications that are tightly integrated and coupled to the core system-of-records on the mainframe,” Mitran says.

This offers many advantages, including:

  • Significantly simplifying the operational environment for improved resilience and better security
  • Streamlined applications so they can be managed within a single footprint on z Systems
  • Improved response time from consolidating and integrating the workload

IBM Competitive Project Office internal tests have found with IBM z Systems Integrated Information Processor and special mobile and cloud pricing, Java on z Systems can provide 16 to 67 percent better total cost of acquisition compared to similar solutions where the application sits off-platform.

Clients See Success

IBM has been committed to Java on z Systems for more than a decade, focusing on performance improvements to the core Java Development Kit, and co-design of z Systems hardware and IBM Java VM (JVM) technology. A large proportion of new instructions and hardware facilities introduced in the last four generations of the z Systems process were co-designed with the IBM JVM team, Mitran notes. As a result, Java on z Systems consistently demonstrates about a 1.5x performance advantage over alternative platforms (

Looking to continue to have strong customer service levels as its client base grew, a software and IT service provider looked to Java to help improve performance. After shifting from a distributed system to Java on z/OS, the company noticed better performance, with improvements in database response by more than 5x during peak periods. “This is a great testament to the value proposition of integrating the Java workload with the system of record and transactional environment,” Mitran says.

Because Java is integrated and available across the middleware portfolio, clients can easily leverage the language with their existing systems. For example, German-based banking IT provider Fiducia & GAD IT AG uses IMS for transaction procession in their core-banking infrastructure. Fiducia & GAD wanted to take advantage of Java for the business logic running inside IMS.

“By doing so, Fiducia & GAD is getting the best of both worlds—the infrastructure and the qualities of service of mission-critical z Systems middleware like IMS, while leveraging the modern ecosystem and capabilities of the Java language,” Mitran says. “Java in IMS gives Fiducia & GAD a means for quickly and effectively developing simpler and more robust solutions to meet the needs of their clients while leveraging new skills and new ecosystems.”

Improvements are also seen when applied to other batch and transaction processor environments, including WebSphere, DB2 and CICS. (Read an example of how Java can be used in CICS in “Create a DevOps Pipeline for Java Applications in CICS” at (

Looking Forward

Modern skills are an important part of the Java value proposition. From DevOps to API enablement, mobile, cloud and beyond, the popular programming language is a way for clients to position themselves for the future, giving them the choice on how to maintain and grow their IT assets. With Java on z Systems, modern tools and ecosystems can be brought to the platform.

Because it’s a mature language, Java is familiar to a broad base of seasoned application developers with an appreciation for enterprise and mission critical computing. This gives z Systems clients more options and flexibility when hiring and recruiting talent, and gives developers more flexibility when working with z Systems. Java is ultimately about choice, Mitran stresses.

“Java on z means clients now have a choice in how they want to address business problems,” he explains. “They can leverage their existing workforce and their existing skills, but they also have the ability to bring in new skills and a broader workforce where necessary. Java means clients have the freedom to solve business problems with the tools they think are best and most appropriate.”