Index: app/src/processing/app/syntax/InputMethodSupport.java
===================================================================
--- app/src/processing/app/syntax/InputMethodSupport.java	(revision 0)
+++ app/src/processing/app/syntax/InputMethodSupport.java	(revision 0)
@@ -0,0 +1,173 @@
+package processing.app.syntax;
+
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.event.InputMethodEvent;
+import java.awt.event.InputMethodListener;
+import java.awt.font.FontRenderContext;
+import java.awt.font.TextAttribute;
+import java.awt.font.TextHitInfo;
+import java.awt.font.TextLayout;
+import java.awt.im.InputMethodRequests;
+import java.text.AttributedCharacterIterator;
+import java.text.AttributedString;
+
+import javax.swing.text.BadLocationException;
+
+public class InputMethodSupport implements InputMethodRequests,
+    InputMethodListener {
+
+  private JEditTextArea textArea;
+
+  private TextLayout composedTextLayout = null;
+
+  private int committed_count = 0;
+
+  private static final int COMPOSING_UNDERBAR_HEIGHT = 5;
+
+  private boolean isComposing;
+
+  public InputMethodSupport(JEditTextArea textArea) {
+    this.textArea = textArea;
+    textArea.enableInputMethods(true);
+    textArea.addInputMethodListener(this);
+    isComposing = false;
+  }
+
+  public boolean getIsComposing() {
+    return isComposing;
+  }
+
+  private Point getCaretLocation() {
+    Point loc = new Point();
+    TextAreaPainter painter = textArea.getPainter();
+    FontMetrics fm = painter.getFontMetrics();
+    int offsetY = fm.getHeight() - 5;
+    int lineIndex = textArea.getCaretLine();
+    loc.y = lineIndex * fm.getHeight() + offsetY;
+    int offsetX = textArea.getCaretPosition()
+        - textArea.getLineStartOffset(lineIndex);
+    loc.x = textArea.offsetToX(lineIndex, offsetX);
+    return loc;
+  }
+
+  public Rectangle getTextLocation(TextHitInfo offset) {
+    Point caret = getCaretLocation();
+    return getCaretRectangle(caret.x, caret.y);
+  }
+
+  private Rectangle getCaretRectangle(int x, int y) {
+    TextAreaPainter painter = textArea.getPainter();
+    Point origin = painter.getLocationOnScreen();
+    int height = painter.getFontMetrics().getHeight();
+    return new Rectangle(origin.x + x, origin.y + y, 0, height);
+  }
+
+  public TextHitInfo getLocationOffset(int x, int y) {
+    return null;
+  }
+
+  public int getInsertPositionOffset() {
+    if (isComposing) {
+      isComposing = false;
+    }
+    return textArea.getCaretPosition();
+  }
+
+  public AttributedCharacterIterator getCommittedText(int beginIndex,
+      int endIndex, AttributedCharacterIterator.Attribute[] attributes) {
+    return (new AttributedString(textArea.getText(beginIndex, endIndex
+        - beginIndex))).getIterator();
+  }
+
+  public int getCommittedTextLength() {
+    return committed_count;
+  }
+
+  public AttributedCharacterIterator cancelLatestCommittedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  public AttributedCharacterIterator getSelectedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  public void inputMethodTextChanged(InputMethodEvent event) {
+    composedTextLayout = null;
+    AttributedCharacterIterator text = event.getText();
+    committed_count = event.getCommittedCharacterCount();
+    if (committed_count == 0) {
+      if (text.getEndIndex() == 0) {
+        caretPositionChanged(event);
+        return;
+      }
+      if (text.getEndIndex() < text.getBeginIndex()) {
+        caretPositionChanged(event);
+        return;
+      }
+      isComposing = true;
+      drawComposingText(text, committed_count);
+      caretPositionChanged(event);
+      return;
+    }
+    commitText(text, committed_count);
+    isComposing = false;
+    caretPositionChanged(event);
+  }
+
+  private void drawComposingText(AttributedCharacterIterator text, int count) {
+    assert ((count == 0 && text.getEndIndex() > 0));
+    Point textLocation = getCaretLocation();
+    invalidateComposingLine(textArea.getPainter(), textLocation.x,
+        textLocation.y);
+    composedTextLayout = getTextLayout(text, count);
+    composedTextLayout.draw((Graphics2D) (textArea.getPainter().getGraphics()),
+        textLocation.x, textLocation.y);
+  }
+
+  private void invalidateComposingLine(TextAreaPainter painter, int x, int y) {
+    Graphics gfx = painter.getGraphics();
+    gfx.setColor(painter.lineHighlightColor);
+    gfx.fillRect(x, y
+        - (painter.getFontMetrics().getHeight() - COMPOSING_UNDERBAR_HEIGHT), //
+        painter.getWidth(), painter.getFontMetrics().getHeight());
+  }
+
+  private void commitText(AttributedCharacterIterator text, int count) {
+    char c;
+    StringBuffer committing = new StringBuffer(count);
+    for (c = text.first(); c != AttributedCharacterIterator.DONE && count > 0; c = text
+        .next(), --count) {
+      committing.append(c);
+    }
+    int caret = textArea.getCaretPosition();
+    String committing_text = committing.toString();
+    try {
+      textArea.getDocument().insertString(caret, committing_text, null);
+    } catch (BadLocationException e) {
+      e.printStackTrace();
+    }
+  }
+
+  private TextLayout getTextLayout(AttributedCharacterIterator text,
+      int committed_count) {
+    AttributedString composed = new AttributedString(text, committed_count,
+        text.getEndIndex());
+    Font font = textArea.getPainter().getFont();
+    FontRenderContext context = ((Graphics2D) (textArea.getPainter()
+        .getGraphics())).getFontRenderContext();
+    composed.addAttribute(TextAttribute.FONT, font);
+    TextLayout layout = new TextLayout(composed.getIterator(), context);
+    return layout;
+  }
+
+  public void caretPositionChanged(InputMethodEvent event) {
+    event.consume();
+  }
+}
Index: app/src/processing/app/syntax/JEditTextArea.java
===================================================================
--- app/src/processing/app/syntax/JEditTextArea.java	(revision 6040)
+++ app/src/processing/app/syntax/JEditTextArea.java	(working copy)
@@ -22,6 +22,7 @@
 import java.awt.*;
 import java.util.Enumeration;
 import java.util.Vector;
+import java.awt.im.InputMethodRequests;
 
 /**
  * jEdit's text area component. It is more suited for editing program
@@ -127,6 +128,16 @@
       });
   }
 
+  /**
+  * Inline Input Method Support for Japanese.
+  */
+  private InputMethodSupport inputMethodSupport = null;
+  public InputMethodRequests getInputMethodRequests() {
+		if (inputMethodSupport == null) {
+			inputMethodSupport = new InputMethodSupport(this);
+		}
+		return inputMethodSupport;
+  }
 
   /**
    * Get current position of the vertical scroll bar. [fry]
@@ -216,7 +227,7 @@
    * Blinks the caret.
    */
   public final void blinkCaret() {
-    if (caretBlinks)  {
+    if (caretBlinks && !((InputMethodSupport)getInputMethodRequests()).getIsComposing())  {
       blink = !blink;
       painter.invalidateSelectedLines();
     } else {