RSyntaxTextArea is a customizable, syntax highlighting text component for Java Swing applications. Out of the box, it supports syntax highlighting for 40+ programming languages, code folding, search and replace, and has add-on libraries for code completion and spell checking. Syntax highlighting for additional languages can be added via tools such as JFlex.

RSyntaxTextArea is available under a modified BSD license. For more information, visit http://bobbylight.github.io/RSyntaxTextArea/.

Available in the Maven Central repository (com.fifesoft:rsyntaxtextarea:XXX).

RSyntaxTextArea uses Gradle to build. To compile, run all unit tests, and create the jar, run:

./gradlew build

Note that RSTA only requires Java 5. To that end, the boot classpath will be set to accommodate this if a variable java5CompileBootClasspath is set to the location of rt.jar in a Java 5 JDK. This can be added to <maven-home>/gradle.properties if desired, to avoid diffs in the project's gradle.properties.

When building with Java 8 or later, the javadoc task currently prints many warnings about Javadoc "issues." This is because doclint is enabled by default in that release of Java. These warnings are harmless, and in a future release will be cleaned up.

RSyntaxTextArea is simply a subclass of JTextComponent, so it can be dropped into any Swing application with ease.

import javax.swing.*;
import org.fife.ui.rtextarea.*;
import org.fife.ui.rsyntaxtextarea.*;

public class TextEditorDemo extends JFrame {

   public TextEditorDemo() {

      JPanel cp = new JPanel(new BorderLayout());

      RSyntaxTextArea textArea = new RSyntaxTextArea(20, 60);
      textArea.setSyntaxEditingStyle(SyntaxConstants.SYNTAX_STYLE_JAVA);
      textArea.setCodeFoldingEnabled(true);
      RTextScrollPane sp = new RTextScrollPane(textArea);
      cp.add(sp);

      setContentPane(cp);
      setTitle("Text Editor Demo");
      setDefaultCloseOperation(EXIT_ON_CLOSE);
      pack();
      setLocationRelativeTo(null);

   }

   public static void main(String[] args) {
      // Start all Swing applications on the EDT.
      SwingUtilities.invokeLater(new Runnable() {
         public void run() {
            new TextEditorDemo().setVisible(true);
         }
      });
   }

}

RSyntaxTextArea provides syntax highlighting, code folding, and many other features out-of-the-box, but when building a code editor you often want to go further. Below is a list of small add-on libraries that add more complex functionality:

• AutoComplete - Adds code completion to RSyntaxTextArea (or any other JTextComponent).
• RSTALanguageSupport - Code completion for RSTA for the following languages: Java, JavaScript, HTML, PHP, JSP, Perl, C, Unix Shell. Built on both RSTA and AutoComplete.
• SpellChecker - Adds squiggle-underline spell checking to RSyntaxTextArea.
• RSTAUI - Common dialogs needed by text editing applications: Find, Replace, Go to Line, File Properties.

• Add an issue on GitHub
• Peruse the wiki
• Ask in the project forum
• Check the project's home page