JHighlight

April 2, 2026 · View on GitHub

A pure Java syntax highlighting library that generates XHTML output from source code. This is a maintained fork of the original jhighlight project with critical bug fixes, particularly for multi-byte character handling.

Features

Pure Java Implementation - No external dependencies for highlighting
Multiple Language Support - Java, Groovy, JavaScript, C++, XML, HTML, XHTML, LZX
XHTML Output - Clean, standards-compliant output
Multi-byte Character Support - Properly handles UTF-8 and other encodings
Command-line Tool - Batch process files and directories
Servlet Filter - Easy integration with web applications
RIFE Template Support - Highlights RIFE template tags

Installation

Maven

<dependency>
    <groupId>org.codelibs</groupId>
    <artifactId>jhighlight</artifactId>
    <version>1.1.0</version>
</dependency>

Gradle

implementation 'org.codelibs:jhighlight:1.1.0'

Quick Start

Programmatic Usage

import org.codelibs.jhighlight.renderer.XhtmlRendererFactory;
import org.codelibs.jhighlight.renderer.Renderer;
import java.io.*;

// Get a renderer for Java code
Renderer renderer = XhtmlRendererFactory.getRenderer("java");

// Highlight code from an input stream
InputStream input = new FileInputStream("Example.java");
OutputStream output = new FileOutputStream("Example.java.html");

renderer.highlight("Example.java", input, output, "UTF-8", false);

Command-line Usage

# Highlight a single file
java -jar jhighlight.jar MyClass.java

# Highlight all files in a directory
java -jar jhighlight.jar src/

# Specify output directory and encoding
java -jar jhighlight.jar -d output -e UTF-8 src/

# Generate fragments instead of complete HTML documents
java -jar jhighlight.jar --fragment MyClass.java

Command-line Options

Option	Description
`--verbose`	Output progress messages
`--fragment`	Generate HTML fragments instead of complete documents
`-d <dir>`	Specify destination directory for output files
`-e <encoding>`	Specify file encoding (default: UTF-8)

Supported Languages

Language	File Extensions	Renderer Type
Java	`.java`	`java`
Groovy	`.groovy`	`groovy`
BeanShell	`.bsh`, `.beanshell`	`beanshell` / `bsh`
JavaScript	`.js`	(via factory)
C++	`.cpp`, `.cxx`, `.c++`	`cpp` / `cxx` / `c++`
XML	`.xml`	`xml`
HTML	`.html`, `.htm`	`html`
XHTML	`.xhtml`	`xhtml`
LZX	`.lzx`	`lzx`

Getting Available Renderers

import org.codelibs.jhighlight.renderer.XhtmlRendererFactory;

Set<String> supportedTypes = XhtmlRendererFactory.getSupportedTypes();
System.out.println("Supported types: " + supportedTypes);

Migration from Original JHighlight

Why This Fork?

The original jhighlight library (from jhighlight.dev.java.net) had critical issues with multi-byte character handling, causing garbled output for source files containing UTF-8 characters, Japanese, Chinese, Korean, and other non-ASCII text. This fork fixes those issues and is actively maintained.

Migrating from Apache Tika

If you're using Apache Tika (which depends on the original jhighlight), you'll need to exclude the old dependency and include this version:

<dependency>
    <groupId>org.apache.tika</groupId>
    <artifactId>tika-parsers</artifactId>
    <version>1.6</version>
    <exclusions>
        <exclusion>
            <groupId>com.uwyn</groupId>
            <artifactId>jhighlight</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>org.codelibs</groupId>
    <artifactId>jhighlight</artifactId>
    <version>1.1.0</version>
</dependency>

Package Changes

This fork maintains the original package structure with additions:

Original packages: com.uwyn.jhighlight.*
New packages: org.codelibs.jhighlight.*

Most classes are now available in the org.codelibs.jhighlight package for better namespace management.

Building from Source

Requirements

Java 17 or higher
Maven 3.8 or higher

Build Steps

# Clone the repository
git clone https://github.com/codelibs/jhighlight.git
cd jhighlight

# Build with Maven
mvn clean install

# Run tests
mvn test

# Generate code coverage report
mvn jacoco:report

The compiled JAR will be available in the target/ directory.

Advanced Usage

Using as a Servlet Filter

import org.codelibs.jhighlight.servlet.HighlightFilter;

// Configure in web.xml
<filter>
    <filter-name>HighlightFilter</filter-name>
    <filter-class>org.codelibs.jhighlight.servlet.HighlightFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>HighlightFilter</filter-name>
    <url-pattern>*.java</url-pattern>
</filter-mapping>

Custom Styling

The generated XHTML includes CSS classes that you can style:

<span class="java_keyword">public</span>
<span class="java_type">class</span>
<span class="java_plain">Example</span>

Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.

Development Guidelines

Follow existing code style and conventions
Add unit tests for new features
Ensure all tests pass: mvn test
Update documentation as needed

License

This project is dual-licensed under:

You may choose either license to govern your use of this software.

Acknowledgments

Original JHighlight project by Geert Bevin
Maintained by CodeLibs Project
Original project: https://jhighlight.dev.java.net/