Index: app/src/processing/app/syntax/InputMethodSupport.java
===================================================================
--- app/src/processing/app/syntax/InputMethodSupport.java	(revision 6115)
+++ app/src/processing/app/syntax/InputMethodSupport.java	(working copy)
@@ -1,173 +0,0 @@
-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 6115)
+++ app/src/processing/app/syntax/JEditTextArea.java	(working copy)
@@ -24,6 +24,8 @@
 import java.util.Vector;
 import java.awt.im.InputMethodRequests;
 
+import processing.app.syntax.im.InputMethodSupport;
+
 /**
  * jEdit's text area component. It is more suited for editing program
  * source code than JEditorPane, because it drops the unnecessary features
@@ -227,7 +229,7 @@
    * Blinks the caret.
    */
   public final void blinkCaret() {
-    if (caretBlinks && !((InputMethodSupport)getInputMethodRequests()).getIsComposing())  {
+    if (caretBlinks)  {
       blink = !blink;
       painter.invalidateSelectedLines();
     } else {
Index: app/src/processing/app/syntax/TextAreaPainter.java
===================================================================
--- app/src/processing/app/syntax/TextAreaPainter.java	(revision 6115)
+++ app/src/processing/app/syntax/TextAreaPainter.java	(working copy)
@@ -12,6 +12,7 @@
 package processing.app.syntax;
 
 import processing.app.*;
+import processing.app.syntax.im.CompositionTextPainter;
 
 import javax.swing.ToolTipManager;
 import javax.swing.text.*;
@@ -33,6 +34,9 @@
   /** Current setting for editor.antialias preference */
   boolean antialias;
 
+  /** A specific painter composed by the InputMethod.*/
+  protected CompositionTextPainter compositionTextPainter;
+
   /**
    * Creates a new repaint manager. This should be not be called
    * directly.
@@ -72,6 +76,16 @@
     eolMarkerColor = defaults.eolMarkerColor;
     eolMarkers = defaults.eolMarkers;
   }
+  
+  /**
+   * Get CompositionTextPainter. if CompositionTextPainter is not created, create it.
+   */
+   public CompositionTextPainter getCompositionTextpainter(){
+     if(compositionTextPainter == null){
+       compositionTextPainter = new CompositionTextPainter(textArea);
+     }
+     return compositionTextPainter;
+   }
 
   /**
    * Returns if this component can be traversed by pressing the
@@ -602,7 +616,12 @@
 
     y += fm.getHeight();
     x = Utilities.drawTabbedText(currentLine,x,y,gfx,this,0);
-
+    /*
+     * Draw characters via input method. 
+     */
+    if (compositionTextPainter != null && compositionTextPainter.hasComposedTextLayout()) {
+      compositionTextPainter.draw(gfx, lineHighlightColor);
+    }
     if (eolMarkers) {
       gfx.setColor(eolMarkerColor);
       gfx.drawString(".",x,y);
@@ -625,7 +644,12 @@
     x = SyntaxUtilities.paintSyntaxLine(currentLine,
                                         currentLineTokens,
                                         styles, this, gfx, x, y);
-
+    /*
+     * Draw characters via input method. 
+     */
+    if (compositionTextPainter != null && compositionTextPainter.hasComposedTextLayout()) {
+      compositionTextPainter.draw(gfx, lineHighlightColor);
+    }
     if (eolMarkers) {
       gfx.setColor(eolMarkerColor);
       gfx.drawString(".",x,y);
Index: app/src/processing/app/syntax/im/CompositionTextManager.java
===================================================================
--- app/src/processing/app/syntax/im/CompositionTextManager.java	(revision 0)
+++ app/src/processing/app/syntax/im/CompositionTextManager.java	(revision 0)
@@ -0,0 +1,187 @@
+package processing.app.syntax.im;
+
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.font.FontRenderContext;
+import java.awt.font.TextAttribute;
+import java.awt.font.TextLayout;
+import java.text.AttributedCharacterIterator;
+import java.text.AttributedString;
+
+import javax.swing.text.BadLocationException;
+
+import processing.app.syntax.JEditTextArea;
+import processing.app.syntax.TextAreaPainter;
+
+/**
+ * This class Manage texts from input method 
+ * by begin-process-end steps.
+ * 
+ * First, if a user start inputing via input method, 
+ * beginCompositionText is called from InputMethodSupport.
+ * Second, the user continues from input method, processCompositionText is called
+ * and reflect user inputs to text area.
+ * Finally the user try to commit text, endCompositionText is called.
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+
+public class CompositionTextManager {
+  private JEditTextArea textArea;
+  private String prevComposeString;
+  private int prevCommittedCount;
+  private boolean isInputProcess;
+  private int initialCaretPosition;
+  public static final int COMPOSING_UNDERBAR_HEIGHT = 5;
+  
+  /**
+   * Create text manager class with a textarea.
+   * @param textArea texarea component for PDE.
+   */
+  public CompositionTextManager(JEditTextArea textArea) {
+    this.textArea = textArea;
+    prevComposeString = "";
+    isInputProcess = false;
+    prevCommittedCount = 0;
+  }
+
+  /**
+   * Get this text manager is whether in input process or not.
+   */
+  public boolean getIsInputProcess() {
+    return isInputProcess;
+  }
+
+  /**
+   * Called when a user begins input from input method.
+   * This method initializes text manager.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void beginCompositionText(AttributedCharacterIterator text, int committed_count) {
+    isInputProcess = true;
+    prevComposeString = "";
+    initialCaretPosition = textArea.getCaretPosition();
+    processCompositionText(text, committed_count);
+  }
+
+  /**
+   * Called when a user processing input characters and
+   * select candidates from input method.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void processCompositionText(AttributedCharacterIterator text, int committed_count) {
+    int layoutCaretPosition = initialCaretPosition + committed_count;
+    CompositionTextPainter compositionPainter = textArea.getPainter().getCompositionTextpainter();
+    compositionPainter.setComposedTextLayout(getTextLayout(text, committed_count), layoutCaretPosition);
+    int textLength = text.getEndIndex() - text.getBeginIndex() - committed_count;
+    StringBuffer unCommitedStringBuf = new StringBuffer(textLength);
+    char c;
+    for (c = text.setIndex(committed_count); c != AttributedCharacterIterator.DONE
+        && textLength > 0; c = text.next(), --textLength) {
+      unCommitedStringBuf.append(c);
+    }
+    String unCommittedString = unCommitedStringBuf.toString();
+    try {
+      if(canRemovePreviousInput(committed_count)){
+        textArea.getDocument().remove(layoutCaretPosition, prevComposeString.length());
+      }
+      textArea.getDocument().insertString(layoutCaretPosition, unCommittedString, null);
+      if(committed_count > 0){
+        initialCaretPosition = initialCaretPosition + committed_count;
+      }
+      prevComposeString = unCommittedString;
+      prevCommittedCount = committed_count;
+    } catch (BadLocationException e) {
+      e.printStackTrace();
+    }
+  }
+
+  private boolean canRemovePreviousInput(int committed_count){
+    return (prevCommittedCount == committed_count || prevCommittedCount > committed_count);
+  }
+
+  /**
+   * Called when a user fixed text from input method or delete all 
+   * composition text. This method resets CompositionTextPainter.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void endCompositionText(AttributedCharacterIterator text, int committed_count) {
+    isInputProcess = false;
+    /*
+     * If there are no committed characters, remove it all from textarea.
+     * This case will happen if a user delete all composing characters by backspace or delete key. 
+     * If it does, these previous characters are needed to be deleted.
+     */
+    if(committed_count == 0){
+      removeNotCommittedText(text);
+    }
+    CompositionTextPainter compositionPainter = textArea.getPainter().getCompositionTextpainter();
+    compositionPainter.invalidateComposedTextLayout(initialCaretPosition + committed_count);
+    prevComposeString = "";
+    isInputProcess = false;
+  }
+
+  private void removeNotCommittedText(AttributedCharacterIterator text){
+    if (prevComposeString.length() == 0) {
+      return;
+    }
+    try {
+        textArea.getDocument().remove(initialCaretPosition, prevComposeString.length());
+    } 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;
+  }
+
+  private Point getCaretLocation() {
+    Point loc = new Point();
+    TextAreaPainter painter = textArea.getPainter();
+    FontMetrics fm = painter.getFontMetrics();
+    int offsetY = fm.getHeight() - COMPOSING_UNDERBAR_HEIGHT;
+    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() {
+    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 AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex) {
+    int length = endIndex - beginIndex;
+    String textAreaString = textArea.getText(beginIndex, length);
+    return new AttributedString(textAreaString).getIterator();
+  }
+
+  public int getInsertPositionOffset() {
+    return textArea.getCaretPosition() * -1;
+  }
+}
Index: app/src/processing/app/syntax/im/CompositionTextPainter.java
===================================================================
--- app/src/processing/app/syntax/im/CompositionTextPainter.java	(revision 0)
+++ app/src/processing/app/syntax/im/CompositionTextPainter.java	(revision 0)
@@ -0,0 +1,125 @@
+package processing.app.syntax.im;
+
+import java.awt.Color;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.font.TextLayout;
+
+import processing.app.syntax.JEditTextArea;
+import processing.app.syntax.TextAreaPainter;
+
+/**
+ * Paint texts from input method. 
+ * Text via input method are transmitted by AttributedCaharacterIterator.
+ * But current PDE's TextAreaPainter can't treat AttributedCaharacterIterator directly.
+ * So this class helps to treat it and paint text.
+ * 
+ * For practical purposes, paint to textarea is done by TextLayout class.
+ * Because TextLayout class is easy to draw composing texts.
+ * (For example, draw underline composing texts, focus when select from candidates text.)
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+public class CompositionTextPainter {
+  private TextLayout composedTextLayout;
+  private int composedBeginCaretPosition = 0;
+  private JEditTextArea textArea;
+
+  /**
+   * Constructor for painter.
+   * @param textarea textarea used by PDE.
+   */
+  public CompositionTextPainter(JEditTextArea textArea) {
+    this.textArea = textArea;
+    composedTextLayout = null;
+  }
+
+  /**
+   * Check the painter has TextLayout.
+   * If a user input via InputMethod, this result will return true.
+   * @param textarea textarea used by PDE.
+   */
+  public boolean hasComposedTextLayout() {
+    return (composedTextLayout != null);
+  }
+  
+  /**
+   * Set TextLayout to the painter.
+   * TextLayout will be created and set by CompositionTextManager.
+   * 
+   * @see CompositionTextManager
+   * @param textarea textarea used by PDE.
+   */
+  public void setComposedTextLayout(TextLayout composedTextLayout, int composedStartCaretPosition) {
+    this.composedTextLayout = composedTextLayout;
+    this.composedBeginCaretPosition = composedStartCaretPosition;
+  }
+
+  /**
+   * Invalidate this TextLayout to set null.
+   * If a user end input via InputMethod, this method will called from CompositionTextManager.endCompositionText
+   */
+  public void invalidateComposedTextLayout(int composedEndCaretPosition) {
+    this.composedTextLayout = null;
+    this.composedBeginCaretPosition = composedEndCaretPosition;
+    //this.composedBeginCaretPosition = textArea.getCaretPosition();
+  }
+  
+  /**
+   * Draw text via input method with composed text information.
+   * This method can draw texts with some underlines to illustrate converting characters. 
+   * 
+   * This method is workaround for TextAreaPainter.
+   * Because, TextAreaPainter can't treat AttributedCharacterIterator directly.
+   * AttributedCharacterIterator has very important information when composing text.
+   * It has a map where are converted characters and committed characters.
+   * Ideally, changing TextAreaPainter method can treat AttributedCharacterIterator is better. But it's very tough!!
+   * So I choose to write some code as a workaround.
+   * 
+   * This draw method is proceeded with the following steps.
+   * 1. Original TextAreaPainter draws characters. 
+   * 2. This refillComposedArea method erase previous paint characters by textarea's background color.
+   *    The refill area is only square that width and height defined by characters with input method.
+   * 3. CompositionTextPainter.draw method paints composed text. It was actually drawn by TextLayout.
+   * 
+   * @param gfx set TextAreaPainter's Graphics object.
+   * @param fillBackGroundColor set textarea's background.
+   */
+  public void draw(Graphics gfx, Color fillBackGroundColor) {
+    assert(composedTextLayout != null);
+    Point composedLoc = getCaretLocation();
+    refillComposedArea(fillBackGroundColor, composedLoc.x, composedLoc.y);
+    composedTextLayout.draw((Graphics2D) gfx, composedLoc.x, composedLoc.y);
+  }
+
+  /**
+   * Fill color to erase characters drawn by original TextAreaPainter. 
+   *  
+   * @param fillColor fill color to erase characters drawn by original TextAreaPainter method.
+   * @param x x-coordinate where to fill.
+   * @param y y-coordinate where to fill.
+   */
+  private void refillComposedArea(Color fillColor, int x, int y) {
+    Graphics gfx = textArea.getPainter().getGraphics();
+    gfx.setColor(fillColor);
+    FontMetrics fm = textArea.getPainter().getFontMetrics();
+    int newY = y - (fm.getHeight() - CompositionTextManager.COMPOSING_UNDERBAR_HEIGHT);
+    int paintHeight = fm.getHeight();
+    int paintWidth = (int) composedTextLayout.getBounds().getWidth();
+    gfx.fillRect(x, newY, paintWidth, paintHeight);
+  }
+
+  private Point getCaretLocation() {
+    Point loc = new Point();
+    TextAreaPainter painter = textArea.getPainter();
+    FontMetrics fm = painter.getFontMetrics();
+    int offsetY = fm.getHeight() - CompositionTextManager.COMPOSING_UNDERBAR_HEIGHT;
+    int lineIndex = textArea.getCaretLine();
+    loc.y = lineIndex * fm.getHeight() + offsetY;
+    int offsetX = composedBeginCaretPosition - textArea.getLineStartOffset(lineIndex);
+    loc.x = textArea.offsetToX(lineIndex, offsetX);
+    return loc;
+  }
+}
Index: app/src/processing/app/syntax/im/InputMethodSupport.java
===================================================================
--- app/src/processing/app/syntax/im/InputMethodSupport.java	(revision 0)
+++ app/src/processing/app/syntax/im/InputMethodSupport.java	(revision 0)
@@ -0,0 +1,104 @@
+package processing.app.syntax.im;
+
+import java.awt.Rectangle;
+import java.awt.event.InputMethodEvent;
+import java.awt.event.InputMethodListener;
+import java.awt.font.TextHitInfo;
+import java.awt.im.InputMethodRequests;
+import java.text.AttributedCharacterIterator;
+
+import processing.app.syntax.JEditTextArea;
+
+/**
+ * Support in-line Japanese input for PDE. (Maybe Chinese, Korean and more)
+ * This class is implemented by Java Input Method Framework and handles
+ * If you would like to know more about Java Input Method Framework,
+ * Please see http://java.sun.com/j2se/1.5.0/docs/guide/imf/
+ * 
+ * This class is implemented to fix Bug 854.
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+public class InputMethodSupport implements InputMethodRequests,
+    InputMethodListener {
+
+  private int committed_count = 0;
+  private CompositionTextManager textManager;
+
+  public InputMethodSupport(JEditTextArea textArea) {
+    textManager = new CompositionTextManager(textArea);
+    textArea.enableInputMethods(true);
+    textArea.addInputMethodListener(this);
+  }
+
+  public Rectangle getTextLocation(TextHitInfo offset) {
+    return textManager.getTextLocation();
+  }
+
+  public TextHitInfo getLocationOffset(int x, int y) {
+    return null;
+  }
+
+  public int getInsertPositionOffset() {
+    return textManager.getInsertPositionOffset();
+  }
+
+  public AttributedCharacterIterator getCommittedText(int beginIndex,
+      int endIndex, AttributedCharacterIterator.Attribute[] attributes) {
+    return textManager.getCommittedText(beginIndex, endIndex);
+  }
+
+  public int getCommittedTextLength() {
+    return committed_count;
+  }
+
+  public AttributedCharacterIterator cancelLatestCommittedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  public AttributedCharacterIterator getSelectedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  /**
+   * Handles events from InputMethod.
+   * This method judges whether beginning of input or 
+   * progress of input or end and call related method.
+   * 
+   * @param event event from Input Method.
+   */
+  public void inputMethodTextChanged(InputMethodEvent event) {
+    AttributedCharacterIterator text = event.getText();
+    committed_count = event.getCommittedCharacterCount();
+    if(isBeginInputProcess(text, textManager)){
+      textManager.beginCompositionText(text, committed_count);
+      caretPositionChanged(event);
+      return;
+    }
+    if (isInputProcess(text)){
+      textManager.processCompositionText(text, committed_count);
+      caretPositionChanged(event);
+      return;
+    }
+    textManager.endCompositionText(text, committed_count);
+    caretPositionChanged(event);
+  }
+
+  private boolean isBeginInputProcess(AttributedCharacterIterator text, CompositionTextManager textManager){
+    if(text == null)
+      return false;
+    return (isInputProcess(text) && !textManager.getIsInputProcess());
+  }
+
+  private boolean isInputProcess(AttributedCharacterIterator text){
+    if(text == null)
+      return false;
+    return (text.getEndIndex() - (text.getBeginIndex() + committed_count) > 0);
+  }
+
+  public void caretPositionChanged(InputMethodEvent event) {
+    event.consume();
+  }
+}
Index: app/src/processing/app/syntax/im/CompositionTextManager.java
===================================================================
--- app/src/processing/app/syntax/im/CompositionTextManager.java	(revision 0)
+++ app/src/processing/app/syntax/im/CompositionTextManager.java	(revision 0)
@@ -0,0 +1,187 @@
+package processing.app.syntax.im;
+
+import java.awt.Font;
+import java.awt.FontMetrics;
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.Rectangle;
+import java.awt.font.FontRenderContext;
+import java.awt.font.TextAttribute;
+import java.awt.font.TextLayout;
+import java.text.AttributedCharacterIterator;
+import java.text.AttributedString;
+
+import javax.swing.text.BadLocationException;
+
+import processing.app.syntax.JEditTextArea;
+import processing.app.syntax.TextAreaPainter;
+
+/**
+ * This class Manage texts from input method 
+ * by begin-process-end steps.
+ * 
+ * First, if a user start inputing via input method, 
+ * beginCompositionText is called from InputMethodSupport.
+ * Second, the user continues from input method, processCompositionText is called
+ * and reflect user inputs to text area.
+ * Finally the user try to commit text, endCompositionText is called.
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+
+public class CompositionTextManager {
+  private JEditTextArea textArea;
+  private String prevComposeString;
+  private int prevCommittedCount;
+  private boolean isInputProcess;
+  private int initialCaretPosition;
+  public static final int COMPOSING_UNDERBAR_HEIGHT = 5;
+  
+  /**
+   * Create text manager class with a textarea.
+   * @param textArea texarea component for PDE.
+   */
+  public CompositionTextManager(JEditTextArea textArea) {
+    this.textArea = textArea;
+    prevComposeString = "";
+    isInputProcess = false;
+    prevCommittedCount = 0;
+  }
+
+  /**
+   * Get this text manager is whether in input process or not.
+   */
+  public boolean getIsInputProcess() {
+    return isInputProcess;
+  }
+
+  /**
+   * Called when a user begins input from input method.
+   * This method initializes text manager.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void beginCompositionText(AttributedCharacterIterator text, int committed_count) {
+    isInputProcess = true;
+    prevComposeString = "";
+    initialCaretPosition = textArea.getCaretPosition();
+    processCompositionText(text, committed_count);
+  }
+
+  /**
+   * Called when a user processing input characters and
+   * select candidates from input method.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void processCompositionText(AttributedCharacterIterator text, int committed_count) {
+    int layoutCaretPosition = initialCaretPosition + committed_count;
+    CompositionTextPainter compositionPainter = textArea.getPainter().getCompositionTextpainter();
+    compositionPainter.setComposedTextLayout(getTextLayout(text, committed_count), layoutCaretPosition);
+    int textLength = text.getEndIndex() - text.getBeginIndex() - committed_count;
+    StringBuffer unCommitedStringBuf = new StringBuffer(textLength);
+    char c;
+    for (c = text.setIndex(committed_count); c != AttributedCharacterIterator.DONE
+        && textLength > 0; c = text.next(), --textLength) {
+      unCommitedStringBuf.append(c);
+    }
+    String unCommittedString = unCommitedStringBuf.toString();
+    try {
+      if(canRemovePreviousInput(committed_count)){
+        textArea.getDocument().remove(layoutCaretPosition, prevComposeString.length());
+      }
+      textArea.getDocument().insertString(layoutCaretPosition, unCommittedString, null);
+      if(committed_count > 0){
+        initialCaretPosition = initialCaretPosition + committed_count;
+      }
+      prevComposeString = unCommittedString;
+      prevCommittedCount = committed_count;
+    } catch (BadLocationException e) {
+      e.printStackTrace();
+    }
+  }
+
+  private boolean canRemovePreviousInput(int committed_count){
+    return (prevCommittedCount == committed_count || prevCommittedCount > committed_count);
+  }
+
+  /**
+   * Called when a user fixed text from input method or delete all 
+   * composition text. This method resets CompositionTextPainter.
+   * 
+   * @param text Text from InputMethodEvent.
+   * @param commited_count Numbers of committed characters in text. 
+   */
+  public void endCompositionText(AttributedCharacterIterator text, int committed_count) {
+    isInputProcess = false;
+    /*
+     * If there are no committed characters, remove it all from textarea.
+     * This case will happen if a user delete all composing characters by backspace or delete key. 
+     * If it does, these previous characters are needed to be deleted.
+     */
+    if(committed_count == 0){
+      removeNotCommittedText(text);
+    }
+    CompositionTextPainter compositionPainter = textArea.getPainter().getCompositionTextpainter();
+    compositionPainter.invalidateComposedTextLayout(initialCaretPosition + committed_count);
+    prevComposeString = "";
+    isInputProcess = false;
+  }
+
+  private void removeNotCommittedText(AttributedCharacterIterator text){
+    if (prevComposeString.length() == 0) {
+      return;
+    }
+    try {
+        textArea.getDocument().remove(initialCaretPosition, prevComposeString.length());
+    } 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;
+  }
+
+  private Point getCaretLocation() {
+    Point loc = new Point();
+    TextAreaPainter painter = textArea.getPainter();
+    FontMetrics fm = painter.getFontMetrics();
+    int offsetY = fm.getHeight() - COMPOSING_UNDERBAR_HEIGHT;
+    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() {
+    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 AttributedCharacterIterator getCommittedText(int beginIndex, int endIndex) {
+    int length = endIndex - beginIndex;
+    String textAreaString = textArea.getText(beginIndex, length);
+    return new AttributedString(textAreaString).getIterator();
+  }
+
+  public int getInsertPositionOffset() {
+    return textArea.getCaretPosition() * -1;
+  }
+}
Index: app/src/processing/app/syntax/im/CompositionTextPainter.java
===================================================================
--- app/src/processing/app/syntax/im/CompositionTextPainter.java	(revision 0)
+++ app/src/processing/app/syntax/im/CompositionTextPainter.java	(revision 0)
@@ -0,0 +1,125 @@
+package processing.app.syntax.im;
+
+import java.awt.Color;
+import java.awt.FontMetrics;
+import java.awt.Graphics;
+import java.awt.Graphics2D;
+import java.awt.Point;
+import java.awt.font.TextLayout;
+
+import processing.app.syntax.JEditTextArea;
+import processing.app.syntax.TextAreaPainter;
+
+/**
+ * Paint texts from input method. 
+ * Text via input method are transmitted by AttributedCaharacterIterator.
+ * But current PDE's TextAreaPainter can't treat AttributedCaharacterIterator directly.
+ * So this class helps to treat it and paint text.
+ * 
+ * For practical purposes, paint to textarea is done by TextLayout class.
+ * Because TextLayout class is easy to draw composing texts.
+ * (For example, draw underline composing texts, focus when select from candidates text.)
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+public class CompositionTextPainter {
+  private TextLayout composedTextLayout;
+  private int composedBeginCaretPosition = 0;
+  private JEditTextArea textArea;
+
+  /**
+   * Constructor for painter.
+   * @param textarea textarea used by PDE.
+   */
+  public CompositionTextPainter(JEditTextArea textArea) {
+    this.textArea = textArea;
+    composedTextLayout = null;
+  }
+
+  /**
+   * Check the painter has TextLayout.
+   * If a user input via InputMethod, this result will return true.
+   * @param textarea textarea used by PDE.
+   */
+  public boolean hasComposedTextLayout() {
+    return (composedTextLayout != null);
+  }
+  
+  /**
+   * Set TextLayout to the painter.
+   * TextLayout will be created and set by CompositionTextManager.
+   * 
+   * @see CompositionTextManager
+   * @param textarea textarea used by PDE.
+   */
+  public void setComposedTextLayout(TextLayout composedTextLayout, int composedStartCaretPosition) {
+    this.composedTextLayout = composedTextLayout;
+    this.composedBeginCaretPosition = composedStartCaretPosition;
+  }
+
+  /**
+   * Invalidate this TextLayout to set null.
+   * If a user end input via InputMethod, this method will called from CompositionTextManager.endCompositionText
+   */
+  public void invalidateComposedTextLayout(int composedEndCaretPosition) {
+    this.composedTextLayout = null;
+    this.composedBeginCaretPosition = composedEndCaretPosition;
+    //this.composedBeginCaretPosition = textArea.getCaretPosition();
+  }
+  
+  /**
+   * Draw text via input method with composed text information.
+   * This method can draw texts with some underlines to illustrate converting characters. 
+   * 
+   * This method is workaround for TextAreaPainter.
+   * Because, TextAreaPainter can't treat AttributedCharacterIterator directly.
+   * AttributedCharacterIterator has very important information when composing text.
+   * It has a map where are converted characters and committed characters.
+   * Ideally, changing TextAreaPainter method can treat AttributedCharacterIterator is better. But it's very tough!!
+   * So I choose to write some code as a workaround.
+   * 
+   * This draw method is proceeded with the following steps.
+   * 1. Original TextAreaPainter draws characters. 
+   * 2. This refillComposedArea method erase previous paint characters by textarea's background color.
+   *    The refill area is only square that width and height defined by characters with input method.
+   * 3. CompositionTextPainter.draw method paints composed text. It was actually drawn by TextLayout.
+   * 
+   * @param gfx set TextAreaPainter's Graphics object.
+   * @param fillBackGroundColor set textarea's background.
+   */
+  public void draw(Graphics gfx, Color fillBackGroundColor) {
+    assert(composedTextLayout != null);
+    Point composedLoc = getCaretLocation();
+    refillComposedArea(fillBackGroundColor, composedLoc.x, composedLoc.y);
+    composedTextLayout.draw((Graphics2D) gfx, composedLoc.x, composedLoc.y);
+  }
+
+  /**
+   * Fill color to erase characters drawn by original TextAreaPainter. 
+   *  
+   * @param fillColor fill color to erase characters drawn by original TextAreaPainter method.
+   * @param x x-coordinate where to fill.
+   * @param y y-coordinate where to fill.
+   */
+  private void refillComposedArea(Color fillColor, int x, int y) {
+    Graphics gfx = textArea.getPainter().getGraphics();
+    gfx.setColor(fillColor);
+    FontMetrics fm = textArea.getPainter().getFontMetrics();
+    int newY = y - (fm.getHeight() - CompositionTextManager.COMPOSING_UNDERBAR_HEIGHT);
+    int paintHeight = fm.getHeight();
+    int paintWidth = (int) composedTextLayout.getBounds().getWidth();
+    gfx.fillRect(x, newY, paintWidth, paintHeight);
+  }
+
+  private Point getCaretLocation() {
+    Point loc = new Point();
+    TextAreaPainter painter = textArea.getPainter();
+    FontMetrics fm = painter.getFontMetrics();
+    int offsetY = fm.getHeight() - CompositionTextManager.COMPOSING_UNDERBAR_HEIGHT;
+    int lineIndex = textArea.getCaretLine();
+    loc.y = lineIndex * fm.getHeight() + offsetY;
+    int offsetX = composedBeginCaretPosition - textArea.getLineStartOffset(lineIndex);
+    loc.x = textArea.offsetToX(lineIndex, offsetX);
+    return loc;
+  }
+}
Index: app/src/processing/app/syntax/im/InputMethodSupport.java
===================================================================
--- app/src/processing/app/syntax/im/InputMethodSupport.java	(revision 0)
+++ app/src/processing/app/syntax/im/InputMethodSupport.java	(revision 0)
@@ -0,0 +1,104 @@
+package processing.app.syntax.im;
+
+import java.awt.Rectangle;
+import java.awt.event.InputMethodEvent;
+import java.awt.event.InputMethodListener;
+import java.awt.font.TextHitInfo;
+import java.awt.im.InputMethodRequests;
+import java.text.AttributedCharacterIterator;
+
+import processing.app.syntax.JEditTextArea;
+
+/**
+ * Support in-line Japanese input for PDE. (Maybe Chinese, Korean and more)
+ * This class is implemented by Java Input Method Framework and handles
+ * If you would like to know more about Java Input Method Framework,
+ * Please see http://java.sun.com/j2se/1.5.0/docs/guide/imf/
+ * 
+ * This class is implemented to fix Bug 854.
+ *  
+ * @author Takashi Maekawa (takachin@generative.info)
+ */
+public class InputMethodSupport implements InputMethodRequests,
+    InputMethodListener {
+
+  private int committed_count = 0;
+  private CompositionTextManager textManager;
+
+  public InputMethodSupport(JEditTextArea textArea) {
+    textManager = new CompositionTextManager(textArea);
+    textArea.enableInputMethods(true);
+    textArea.addInputMethodListener(this);
+  }
+
+  public Rectangle getTextLocation(TextHitInfo offset) {
+    return textManager.getTextLocation();
+  }
+
+  public TextHitInfo getLocationOffset(int x, int y) {
+    return null;
+  }
+
+  public int getInsertPositionOffset() {
+    return textManager.getInsertPositionOffset();
+  }
+
+  public AttributedCharacterIterator getCommittedText(int beginIndex,
+      int endIndex, AttributedCharacterIterator.Attribute[] attributes) {
+    return textManager.getCommittedText(beginIndex, endIndex);
+  }
+
+  public int getCommittedTextLength() {
+    return committed_count;
+  }
+
+  public AttributedCharacterIterator cancelLatestCommittedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  public AttributedCharacterIterator getSelectedText(
+      AttributedCharacterIterator.Attribute[] attributes) {
+    return null;
+  }
+
+  /**
+   * Handles events from InputMethod.
+   * This method judges whether beginning of input or 
+   * progress of input or end and call related method.
+   * 
+   * @param event event from Input Method.
+   */
+  public void inputMethodTextChanged(InputMethodEvent event) {
+    AttributedCharacterIterator text = event.getText();
+    committed_count = event.getCommittedCharacterCount();
+    if(isBeginInputProcess(text, textManager)){
+      textManager.beginCompositionText(text, committed_count);
+      caretPositionChanged(event);
+      return;
+    }
+    if (isInputProcess(text)){
+      textManager.processCompositionText(text, committed_count);
+      caretPositionChanged(event);
+      return;
+    }
+    textManager.endCompositionText(text, committed_count);
+    caretPositionChanged(event);
+  }
+
+  private boolean isBeginInputProcess(AttributedCharacterIterator text, CompositionTextManager textManager){
+    if(text == null)
+      return false;
+    return (isInputProcess(text) && !textManager.getIsInputProcess());
+  }
+
+  private boolean isInputProcess(AttributedCharacterIterator text){
+    if(text == null)
+      return false;
+    return (text.getEndIndex() - (text.getBeginIndex() + committed_count) > 0);
+  }
+
+  public void caretPositionChanged(InputMethodEvent event) {
+    event.consume();
+  }
+}