Fresche Taps AI For New RPG-To-Java Conversion Tool

November 10, 2025 Alex Woodie

Fresche Solutions has launched X-Modernize AI, a new offering that uses generative AI technology to convert legacy RPG and Synon code to modern Java. The software, which is based on large language models and its X-Analysis cross-reference and code understanding tool, will speed up code conversion projects by a significant amount, the company claims.

Fresche Solutions is no stranger to legacy modernization projects and tools that convert RPG code into languages like Java, PHP, and .NET. In fact, the company’s very first announcement after it changed its name from Speedware to Fresche Legacy way back in 2012 was the acquisition of a Germany company that developed a tool that converted RPG code to Java and .NET.

Fast forward 13 years, and Fresche Solutions (as the company is now called) is still developing tools and providing services aimed at helping IBM i shops modernize their legacy RPG applications, whether by building Web and mobile front-ends onto existing RPG applications, modernizing the database layer, or by converting RPG code or rewriting RPG apps in different languages.

With the launch of X-Modernize AI, the company is taking a brand-new approach to code conversion. Instead of using a rules-based code converter, the company is putting the critical code conversion step into the hands of the latest LLMs developed by companies like Anthropic.

“We went all-in on basically a complete rewrite of our technology using AI,” said Marcel Sarrasin, general manager of modernization solutions at Fresche. “This is the biggest announcement we have had.”

Fresche isn’t just copying raw RPG code into Anthropic Claude (or other LLMs), asking it to rewrite it in Java, and then pasting what comes out. While that might yield code that could run, it would invite many more problems that developers would eventually have to deal with.

Instead, Fresche says it is taking a pragmatic approach to leveraging LLMs with X-Modernize AI, and only relies on AI for specific components of a modernization project. Fresche has taken steps to ensure that the Java output from X-Modernize AI is on par with the best hand-written code and will be maintainable by any Java programmer moving forward. “Our goal is business functional equivalence,” Sarrasin said. “It’s got to do what it did before.”

The process starts with X-Analysis, the trusted cross reference tool that Fresche obtained with its acquisition of Databorough many years ago. X-Analysis provides a deep understanding of how the RPG applications run, and this enables Fresche to extract the underlying business rules that can be buried in RPG code. The software then calls upon a series of AI agents to generate Java code from the extracted business rules, not the RPG code itself.

While the actual code conversion can proceed in a stepwise fashion (i.e. convert the most critical apps and screens first), Fresche takes a whole-of-application approach to code understanding with X-Modernize AI. This allows it to identify common programs that are shared across the entire RPG application, which can minimize the scope of the project, and minimize the chance for an LLM to mess something up.

For instance, left to its own devices, an LLM will figure out a new way to convert RPG date codes for every program. With X-Modernize AI, Fresche steps in and flags different components, like the RPG date codes, to ensure that a standardized conversion takes place every time. It’s about knowing where AI is weak, and where it is strong, and taking steps to bring humans in the loop to ensure a good result, Sarrasin said.

“AI can get pretty creative. So we have put in a lot of work how to constrain the hallucinations,” he told IT Jungle. “We’ll flag this and say ‘This is something that a human will need to look at.’ We still have what’s called the last mile. A developer will need to go and look at this stuff still.”

While there are exit points (for lack of a better word) for humans to step in, Fresche has sought to automate as much of the code conversion process as possible with X-Modernize AI. The business rule extraction and validation happens automatically, said Fresche chief technology officer John Clark. “It will build a plan and then execute the plan for application modernization. That’s all inside the factory,” he added.

X-Modernize AI also generates test cases automatically, which can help speed up the unit testing process for developers. This will allow the code conversion process to plug right into the DevOps processes that they currently use, Fresch said.

X-Modernize AI works with fixed-format RPG III and RPG IV code, as well as code developed in Synon, the 4GL that was popular in the 1990s. The product is currently set up to generate standard Java 17 code that runs on any operating system with a JVM; additional targets (such as .NET or PHP) could be added in the future based on customer demand, the company says. The software also supports DDS to DDL conversion, and will support a variety of database targets, including Db2 for i, Postgres, Oracle, and MySQL, the company says. Greenscreen interfaces are transformed to JavaScript using the React framework; the company may support other JavaScript frameworks, such as Angular or Vue, Fresche said.

IBM i and RPG are unique as far as computing platforms and languages go, and mainstream LLMs don’t necessarily have a good grip on them yet. That’s one reason why Fresche relies on a mix of different LLMs with X-Modernize AI. Customers that are concerned about sending their code to any particular AI model builder will have other options, the company said.

That uniqueness can also mean headaches for anyone trying to cut and paste their RPG code into ChatGPT and get anything out of it. That’s where Fresche is stepping in to make sure that the output from the LLMs is usable. For instance, RPG programmers have no problem dealing with things like the move command, data areas, and data queues, but they cause havoc for LLMs, Clark said.

“There’s a lot of different tools that RPG developers have used to create applications over the years that create landmines for a do-it-yourselfer with ChatGPT,” he said. “There are some places where we take the steering wheel away from the LLMs, where we know that creativity is not in our best interest.”

Fresche is offering subscriptions for X-Modernize AI. Pricing was not provided. More information can be found on the Fresche website at www.freschesolutions.com.

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