News

Java Compiler CheerpJ Adds Support for WebAssembly Runtime Modules

• By John K. Waters
• February 5, 2020

Leaning Technologies announced the second major release of its CheerpJ Java compiler for the Web this week. This release, which was two years in the making, adds WebAssembly runtime modules, which are used whenever the runtime package is computationally heavy.

CheerpJ is a Java bytecode-to-JavaScript compiler that is compatible with 100 percent of Java. It's designed to compile any Java SE application, library or Java applet into a JavaScript application.

Stefano De Rossi, company founder and managing director, announced the update in a blog post. He divided CheerpJ users into three categories: those who need to convert legacy Java apps and Java Applets to HTML5 with minimal or no effort to extend their life until deprecation or a replacement native HTML application comes along; those who need to migrate an existing Java client to a browser-based Web application; and those using converted Java libraries as part of a native web application.

"The majority of the commercial users of CheerpJ fall into the first two categories," he wrote. "CheerpJ is not intended for writing a Web application from scratch, except in the case exemplified in point 3 above. We do not see CheerpJ as a Blazor-equivalent for Java, although anyone is welcome to build a framework on top of it."

Version 2.0 adds WebAssembly runtime modules to improve runtime speed and reduce the size of packages in situations that cause high computational cost -- things like font rendering. It also updates the AOT compiler and adds a new API for receiving preloading notifications. And there's a new read-only filesystem in /str/ for strings or binary data and extended support for charsets.

CheerpJ 2.0 is available for Windows, macOS, and Linux in three editions: Community, Essential and Enterprise. It can be downloaded from GitHub.