Added syntax highlighting, and auto complete (doesn't seem to work though)

.classpath

@@ -1,10 +1,30 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <classpath>
+	<classpathentry kind="src" path="src"/>
 	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-17">
 		<attributes>
 			<attribute name="module" value="true"/>
 		</attributes>
 	</classpathentry>
-	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="lib" path="lib/rsyntaxtextarea-3.2.1-20220312.195807-1.jar">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="lib" path="lib/autocomplete-3.2.1-20220313.002528-1.jar">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="lib" path="lib/languagesupport-3.2.0-20220626.210742-1.jar">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
+	<classpathentry kind="lib" path="lib/rhino-1.7.14.jar">
+		<attributes>
+			<attribute name="module" value="true"/>
+		</attributes>
+	</classpathentry>
 	<classpathentry kind="output" path="bin"/>
 </classpath>

src/com/okseby/io/Open.java

@@ -1,7 +1,7 @@
 package com.okseby.io;
 
 public class Open {
-	public Open() {
+	public void readFile(String path) {
 		
 	}
 }

src/com/okseby/utils/Providers.java

@@ -0,0 +1,38 @@
+package com.okseby.utils;
+
+import org.fife.ui.autocomplete.*;
+
+public class Providers {
+	public static CompletionProvider createCompletionProvider() {
+
+	      // A DefaultCompletionProvider is the simplest concrete implementation
+	      // of CompletionProvider. This provider has no understanding of
+	      // language semantics. It simply checks the text entered up to the
+	      // caret position for a match against known completions. This is all
+	      // that is needed in the majority of cases.
+	      DefaultCompletionProvider provider = new DefaultCompletionProvider();
+
+	      // Add completions for all Java keywords. A BasicCompletion is just
+	      // a straightforward word completion.
+	      provider.addCompletion(new BasicCompletion(provider, "abstract"));
+	      provider.addCompletion(new BasicCompletion(provider, "assert"));
+	      provider.addCompletion(new BasicCompletion(provider, "break"));
+	      provider.addCompletion(new BasicCompletion(provider, "case"));
+	      // ... etc ...
+	      provider.addCompletion(new BasicCompletion(provider, "transient"));
+	      provider.addCompletion(new BasicCompletion(provider, "try"));
+	      provider.addCompletion(new BasicCompletion(provider, "void"));
+	      provider.addCompletion(new BasicCompletion(provider, "volatile"));
+	      provider.addCompletion(new BasicCompletion(provider, "while"));
+
+	      // Add a couple of "shorthand" completions. These completions don't
+	      // require the input text to be the same thing as the replacement text.
+	      provider.addCompletion(new ShorthandCompletion(provider, "sysout",
+	            "System.out.println(", "System.out.println("));
+	      provider.addCompletion(new ShorthandCompletion(provider, "syserr",
+	            "System.err.println(", "System.err.println("));
+
+	      return provider;
+
+	   }
+}

src/com/okseby/win/Window.java

@@ -5,7 +5,6 @@ import java.awt.Color;
 import java.awt.Dimension;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
-
 import javax.swing.Box;
 import javax.swing.JButton;
 import javax.swing.JFrame;
@@ -13,10 +12,17 @@ import javax.swing.JMenu;
 import javax.swing.JMenuBar;
 import javax.swing.JMenuItem;
 import javax.swing.JPanel;
-import javax.swing.JTextArea;
 import javax.swing.UIManager;
 import javax.swing.border.EtchedBorder;
 
+import org.fife.rsta.ac.LanguageSupportFactory;
+import org.fife.ui.autocomplete.*;
+import org.fife.ui.rsyntaxtextarea.RSyntaxTextArea;
+import org.fife.ui.rsyntaxtextarea.SyntaxConstants;
+import org.fife.ui.rtextarea.RTextScrollPane;
+
+import com.okseby.utils.Providers;
+
 public class Window implements Runnable {
 	JFrame window;
 	JMenuBar menuBar;
@@ -26,7 +32,10 @@ public class Window implements Runnable {
 	JMenuItem fileMenuItem1, fileMenuItem2, fileMenuItem3;
 	JPanel fileExplorer;
 	JPanel mainPanel;
-	JTextArea textArea;
+	RSyntaxTextArea textArea;
+	RTextScrollPane scrollPane;
+	CompletionProvider completionProvider;
+	AutoCompletion autoComplete;
 	
 	String title;
 	double version;
@@ -71,7 +80,14 @@ public class Window implements Runnable {
 		
 		mainPanel.setLayout(new BorderLayout());
 		mainPanel.setBorder(new EtchedBorder());
-		mainPanel.add(textArea);
+		mainPanel.add(scrollPane);
+		
+		textArea.setSyntaxEditingStyle(SyntaxConstants.SYNTAX_STYLE_JAVA);
+		textArea.setCodeFoldingEnabled(true);
+		
+		LanguageSupportFactory.get().register(textArea);
+		
+		autoComplete.install(textArea);
 		
 		window.add(fileExplorer, BorderLayout.WEST);
 		window.add(mainPanel);
@@ -95,7 +111,10 @@ public class Window implements Runnable {
 		fileMenuItem3 = new JMenuItem("Close File");
 		fileExplorer = new JPanel();
 		mainPanel = new JPanel();
-		textArea = new JTextArea();
+		textArea = new RSyntaxTextArea();
+		scrollPane = new RTextScrollPane(textArea);
+		completionProvider = Providers.createCompletionProvider();
+		autoComplete = new AutoCompletion(completionProvider);
 	}
 
 	@Override

src/module-info.java

@@ -4,4 +4,7 @@
  */
 module scrypt {
 	requires java.desktop;
+	requires org.fife.RSyntaxTextArea;
+	requires autocomplete;
+	requires languagesupport;
 }