Legacy Java Desktop Infrastructure Decommissioning with CheerpJ

Product Used:

Our client is a renowned global financial institution that excels in wealth management and investment banking, maintaining a reputation for precision and innovation in the finance industry.

The Problem

Our client faced a critical challenge in eliminating the need for legacy Desktop Java Runtime Environment (JRE) installations from any internal users needing to access its Configuration Management Database (CMDB) platform.

The complexity of an eventual upgrade or decommissioning project threatened to extend beyond acceptable time frames if handled internally. In search of a solution, the company explored CheerpJ, a technology designed to seamlessly access legacy Java Desktop applications on modern browsers.

The objective of the project was to upgrade an existing Java Applet so that it could be run on modern browsers, without a requirement for a local Java installation.

In an initial PoC, CheerpJ was easily integrated into the unmodified Java application, and hosted on the client’s server, allowing the Java application to run on modern browsers, such as Microsoft Edge and Google Chrome. Minor integration issues and defects were swiftly resolved by the Leaning Technologies team, who provided on-site support to overcome challenges related to screen switching, applet sizing, and file system compatibility.

Benefits and Improvements:

The implementation of CheerpJ brought about significant advantages for our client, notably in cost and resource-saving.

Instead of requiring a team of developers to develop a replacement application, a single resource focused on implementing CheerpJ. This efficiency allowed our client to reallocate engineering resources to other high-priority projects. The project’s completion time was drastically reduced from a projected two years to a mere two months.

Moreover, users benefited from improved accessibility, now able to use the tool across multiple browsers (Chrome and Edge), compared to the previously limited compatibility with legacy IE or Edge IE mode.

Challenges and Solutions:

Our client encountered challenges during the initial PoC stage, such as a blank screen when switching views, applet sizing issues, and a file chooser malfunction. With support from the Leaning Technologies team, these challenges were successfully addressed through minimal code adjustments, documented examples, and guidance.

Use Cases and Impact:

While CheerpJ is currently coexisting with the old solution, its deployment has positively impacted our client’s operations. The parallel operation ensures a seamless transition, with users benefiting from enhanced accessibility. The overall improvements in efficiency, reduced costs, and enhanced user experience highlight the positive impact of CheerpJ on our client’s business operations.


Our client successfully navigated the challenges of removing legacy infrastructure by strategically implementing CheerpJ. The integration not only streamlined the migration of Java applications but also yielded significant cost savings, improved efficiency, and enhanced user experience.

What is CheerpJ?

An Enterprise-grade solution to modernise and preserve access to mission-critical Java Applications and Applets by removing the requirement for Java on the client.

CheerpJ converts Java bytecode into WebAssembly and JavaScript, so that it can run natively on modern browsers.

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