Rise of Java on the Mainframe Part of Prevailing Enthusiasm for the Platform
BMC survey finds satisfaction with the mainframe at near-peak levels, while implementation of Java on the platform continues to rise
As director of product management for BMC Software, a significant part of Alan Warhurst’s job is talking to mainframe clients, and these days he is hearing a clear message: Even as they deal with substantial challenges such as implementing modernization initiatives and ushering in a new generation of developers and programmers, mainframe clients are clearly excited about the direction of the platform.
“A couple of weeks ago, I had the pleasure of being with some of our most important customers in the U.S., and I think the sentiment that practically everybody in the room shared with us was that the mainframe really is core to their business,” Warhurst said this fall during a webinar covering BMC’s 2024 mainframe survey report, “Modernizing mainframe investment.”
As IBM touts the mainframe’s momentum, BMC, the Houston-based provider of enterprise software and IT and consulting services, keeps its own numbers. In the company’s annual survey, 94% of respondents held a positive perception of the mainframe. While relativity should be considered—since 2013 this figure hasn’t dipped below 89%—over the past three years, coinciding with the z16’s unveiling in 2022, satisfaction has peaked in the 94-95% range.
Java Helps Satisfaction Stay High
So how is this level positivity prevailing in the world of the modern mainframe? An illustrative example can be found with Java. While Java has long been available on the mainframe—IBM released its first SDK for Java on its System/390 hardware in 1997—it’s become increasingly prominent on the platform.
It’s a means of modernization, and one that’s familiar to most newbie mainframers, as Mark Sigler, BMC’s senior director of product management leading the DevOps portfolio, explains.
“Java on the mainframe is something that I talk about with our customer base all the time,” Sigler told TechChannel. “The mainframe is an excellent platform for certain workloads. When you need that security, that resilience, that throughput and performance—it’s very difficult to try to replicate something like that in a cloud.”
Even with their commitment to the mainframe, clients are also contending with the ongoing skills shortage. “The universities, very few teach COBOL and these platforms like they did back when I was in college a long time ago. Now Java is the primary language that gets taught in universities, so the available talent is principally Java developers,” Sigler said.
More Mainframe Applications Written in Java
The BMC survey shows that the most prolific users, roughly one-third of respondents, are writing anywhere from 25% to more than half of their applications in Java, with this pace holding steady from 2023-2024. However, for some clients that previously were only dipping their toes, there’s been a splash, subtle but noticeable. A year ago, 44% of respondents reported writing 5-25% of their applications in Java; that number stands at 60% in the current survey.
Though a majority of respondents said they’re writing new applications in Java—the percentage grew from 59-64% from 2023-2024—clients are also increasingly rewriting existing applications (44-55% from 2023-2024).
Miocroservices, Modern Interfaces, Cost Savings
Rewriting existing applications in Java offers some clear benefits, as BMC’s John Dannenberg, product manager, explained.
“[Customers] I’ve talked to have said they’re basically looking to create microservices in Java. So it’s not the heart of the application, but some common routines, or maybe things like writing to log files, doing print sets, more service level,” he told TechChannel. “…Now, the big ‘why it’s important to modernize’ is I think with web apps and Android apps and Apple, all those applications, you can’t write that in COBOL. So a lot of those interfaces that people are using now, the modern interfaces are going to be written in Java.”
Another advantage to rewriting applications in Java comes with the ability to deploy the IBM Integrated Information Processor (zIIP) to offload Java-based workloads and reduce costs associated with software licensing.
“You can run Java workloads on the zIIP processor at a fraction of the cost of running, say, COBOL on a general processor in the system,” Sigler explained. “Some of the Db2 stuff also runs on zIIP at a much lower cost. So leveraging the facilities that IBM has and the pricing model of the platform have been big drivers: ‘Hey, this heavy piece of functionality runs a lot; let’s convert it to Java and run it on the zIIP because it handles the workload.’ You could see a significant cost reduction.”
Not Just Java
As critical as Java has become, it’s important to recognize that it’s just a part of the story of the modern mainframe. Developers and programmers are turning to a host of open-source options. Python, which has overtaken Java as the world’s most widely used programming language, is serving as a replacement for Rexx, JCL and other scripting languages. And the fact remains that hundreds of millions of lines of COBOL continue to underpin batch processing and other core functions, and incoming programmers and developers are perfectly capable of picking up the venerable language.
“COBOL is just excellent at what it does,” Sigler said. “If I’ve got working code that’s been very reliable and it’s suitable for a purpose, the right tool for the job, then why would I change? We do see adoption of Java on the mainframe, but it’s kind of a slow and gradual replacement, typically.”
And with certain critical applications, replacing COBOL just isn’t worth the risk, according to Dannenberg. “These applications are typically financial applications that have been running for decades,” he said. “I don’t even think somebody could come up with a QA plan to actually test it thoroughly end-to-end because of the number of years it’s been out there.”
Methodical Replacement Over Wholesale Change
While modernization is no small task, it can be thought of as many individual small tasks.
“Where we see big challenges,” Sigler said, “is when large consulting companies come in with some major mainframe modernization strategy and it’s going to take years and hundreds of consultants, thousands of billable hours. And these are giant projects, and those things are very high-risk, and they fail often.”
Instead, he said, the more effective approach is to methodically replace certain COBOL components. “Do it systematically, bit by bit, and come up with a good application architecture,” Sigler said. “Think about not just fixing the one bug or adding one feature, but making that whole piece of code more efficient, more effective and easier to maintain.”
Keeping the Mainframe Fresh
Happy clients, cutting-edge tech. Has there ever been a better time to be a mainframer? At the very least, these are interesting times.
“Mainframe customers are taking advantage of the fact that IBM is responsive to their needs, keeping the platform fresh and relevant, adding new capabilities,” Sigler said. “They’ve got next-generation processors coming out specifically for AI that will help make that a good platform for a certain AI workloads.”
Keeping an eye toward the future is part of the mainframe community’s makeup, Warhurst said: “I think the mainframe community actually embraces change—new technologies, new approaches—far better than any of the press suggests.”