What is CheerpJ?

CheerpJ is a drop-in replacement for the JVM in HTML5, capable of running any Java Application, Applet and Library on modern browsers.

Full JavaRuntime

CheerpJ comes with a full OpenJDK runtime, providing full compatibility with any Java application

Full JVM in WebAssembly

CheerpJ runs Java bytecode thanks to a WebAssembly Just-In-Time compiler

Secure by Design

CheerpJ operates within the browser sandbox, using safe and secure Web APIs for system access

CheerpJ provides a seamless experience of migrating existing Java Applications, developed internally or from third parties, to an HTML5 experience accessible from any modern browser. No plugins and no installations are required from the user.

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Key Features

Full Java environment in HTML5

CheerpJ enables modern browsers to run any Java Application and Applet, as well as Java libraries.

Legacy Modernization

With CheerpJ, you can run legacy Java Applets and Applications on modern browsers, removing the requirement for IE, Edge IE mode, and for a local Java installation.

Effortless Deployment

CheerpJ does not need access to the source code at all, operating at the level of Java bytecode. Third-party libraries, dependencies and obfuscated code pose no issue.

JVM replacement

CheerpJ core component is a Java Bytecode JIT compiler in WebAssembly.

Full Runtime

CheerpJ comes with a full OpenJDK runtime environment, ensuring that existing applications ‘will just work’. This includes Java Swing, AWT, and any other runtime component.

Full Classloader Support

CheerpJ can now give full control to the appropriate Classloader for class resolution, including application-provided ones. This completely eliminates incompatibilities caused by duplicated classes as well.

Scalable JNI Architecture

CheerpJ compiles 100% of the OpenJDK native code to WebAssembly, providing a viable path for supporting modern versions of Java and potentially specific point versions if a user requires.

Java-JavaScript Interoperability

CheerpJ provides multiple mechanisms for Java and JavaScript to interoperate.

Networking and System Features

CheerpJ provides a full networking stack (HTTP(s), TCP/IP), as well as support for file access, networking (HTTP and TCP), clipboard, audio, printing, and more.

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