Create animated GIF using imageio

Question

How do you create an animated GIF using the J2SE's javax.imageio classes?
I have been browsing these 3 threads (one of which I participated in) to try and develop an SSCCE of creating an animated GIF.
[Writing out animated gifs with ImageIO?|http://forums.sun.com/thread.jspa?threadID=5204877]
[Wirting image metadata to control animated gif delays |http://forums.java.net/jive/thread.jspa?messageID=214284&]
[Help with GIF writer in imageio|http://www.javakb.com/Uwe/Forum.aspx/java-programmer/32892/Help-with-GIF-writer-in-imageio]
(pity I did not prompt the OP on that last one, to supply an SSCCE.)
Unfortunately, my efforts so far have been dismal. Either, without the IIOMetadata object, the GIF has frames with no delay, and it cycles just once, or with the IIOMetadata object I get an error.
IIOInvalidTreeException: Unknown child of root node!Can anyone point me in the right direction?
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
import java.io.*;
import java.net.URL;
import java.util.Iterator;
import javax.imageio.*;
import javax.imageio.metadata.*;
import javax.imageio.stream.*;
import org.w3c.dom.Node;
class WriteAnimatedGif {
  /** Adapted from code via Brian Burkhalter on
  http://forums.java.net/jive/thread.jspa?messageID=214284& */
  public static Node getRootNode(String delayTime) {
    IIOMetadataNode root =
      new IIOMetadataNode("javax_imageio_gif_stream_1.0");
    IIOMetadataNode gce =
      new IIOMetadataNode("GraphicControlExtension");
    gce.setAttribute("disposalMethod", "none");
    gce.setAttribute("userInputFlag", "FALSE");
    gce.setAttribute("transparentColorFlag", "FALSE");
    gce.setAttribute("delayTime", delayTime);
    gce.setAttribute("transparentColorIndex", "255");
    root.appendChild(gce);
    IIOMetadataNode aes =
      new IIOMetadataNode("ApplicationExtensions");
    IIOMetadataNode ae =
      new IIOMetadataNode("ApplicationExtension");
    ae.setAttribute("applicationID", "NETSCAPE");
    ae.setAttribute("authenticationCode", "2.0");
    byte[] uo = new byte[] {
      (byte)0x21, (byte)0xff, (byte)0x0b,
      (byte)'N', (byte)'E', (byte)'T', (byte)'S',
      (byte)'C', (byte)'A', (byte)'P', (byte)'E',
      (byte)'2', (byte)'.', (byte)'0',
      (byte)0x03, (byte)0x01, (byte)0x00, (byte)0x00,
      (byte)0x00
    ae.setUserObject(uo);
    aes.appendChild(ae);
    root.appendChild(aes);
    return root;
  /** Adapted from code via GeogffTitmus on
  http://forums.sun.com/thread.jspa?messageID=9988198 */
  public static File saveAnimate(
    BufferedImage[] frames,
    String name,
    String delayTime) throws Exception {
    File file = null;
    file = new File(name+".gif");
    Node root = getRootNode(delayTime);
    ImageWriter iw = ImageIO.getImageWritersByFormatName("gif").next();
    ImageOutputStream ios = ImageIO.createImageOutputStream(file);
    iw.setOutput(ios);
    //IIOImage ii = new IIOImage(frames[0], null, null);
    //IIOMetadata im = iw.getDefaultStreamMetadata(null);
    //IIOMetadata im = new AnimatedIIOMetadata();
    //im.setFromTree("gif", root);
    iw.prepareWriteSequence(null);
    for (int i = 0; i < frames.length; i++) {
      BufferedImage src = frames;
ImageWriteParam iwp = iw.getDefaultWriteParam();
IIOMetadata metadata = iw.getDefaultStreamMetadata(iwp);
System.out.println( "IIOMetadata: " + metadata );
//metadata.mergeTree(metadata.getNativeMetadataFormatName(), root);
metadata.setFromTree(metadata.getNativeMetadataFormatName(), root);
//Node root = metadata.getAsTree("javax_imageio_gif_image_1.0");
IIOImage ii = new IIOImage(src, null, metadata);
iw.writeToSequence( ii, (ImageWriteParam)null);
iw.endWriteSequence();
ios.close();
return file;
public static void main(String[] args) throws Exception {
// uncomment the other two if you like, but we can
// see it work or fail with just the first and last.
String[] names = {
"bronze",
//"silver",
//"gold",
"platinum"
String pre = "http://forums.sun.com/im/";
String suff = "-star.gif";
BufferedImage[] frames = new BufferedImage[names.length];
for (int ii=0; ii<names.length; ii++) {
URL url = new URL(pre + names[ii] + suff);
System.out.println(url);
frames[ii] = ImageIO.read(url);
File f = saveAnimate(frames, "animatedstars", "500");
JOptionPane.showMessageDialog( null, new ImageIcon(f.toURI().toURL()) );
Desktop.getDesktop().open(f);
ImageInputStream iis = ImageIO.createImageInputStream(f);
//System.out.println("ImageReader: " + ir1);
//System.out.println("IIOMetadata: " + ir1.getStreamMetadata());
Iterator itReaders = ImageIO.getImageReaders(iis);
while (itReaders.hasNext() ) {
ImageReader ir = (ImageReader)itReaders.next();
System.out.println("ImageReader: " + ir);
System.out.println("IIOMetadata: " + ir.getStreamMetadata());

Answer 1

According to imagio's [gif metadata specification|http://java.sun.com/javase/6/docs/api/javax/imageio/metadata/doc-files/gif_metadata.html], the metadata you are specifying is image-specific metadata. The stream metadata is global metadata applicable to all the images.
So change this,
IIOMetadataNode root =
    new IIOMetadataNode("javax_imageio_gif_stream_1.0");to this,
IIOMetadataNode root =
    new IIOMetadataNode("javax_imageio_gif_image_1.0");and this,
IIOMetadata metadata = iw.getDefaultStreamMetadata(iwp);
System.out.println( "IIOMetadata: " + metadata );
//metadata.mergeTree(metadata.getNativeMetadataFormatName(), root);
metadata.setFromTree(metadata.getNativeMetadataFormatName(), root);
//Node root = metadata.getAsTree("javax_imageio_gif_image_1.0");to this,
IIOMetadata metadata = iw.getDefaultImageMetadata(
        new ImageTypeSpecifier(src),null);
System.out.println("IIOMetadata: " + metadata);
metadata.mergeTree(metadata.getNativeMetadataFormatName(), root);Here is your program again, but with the above changes.
import java.awt.*;
import java.awt.image.*;
import javax.swing.*;
import java.io.*;
import java.net.URL;
import java.util.Iterator;
import javax.imageio.*;
import javax.imageio.metadata.*;
import javax.imageio.stream.*;
import org.w3c.dom.Node;
class WriteAnimatedGif {
    /** Adapted from code via Brian Burkhalter on
    http://forums.java.net/jive/thread.jspa?messageID=214284& */
    public static Node getRootNode(String delayTime) {
        IIOMetadataNode root =
                new IIOMetadataNode("javax_imageio_gif_image_1.0");
        IIOMetadataNode gce =
                new IIOMetadataNode("GraphicControlExtension");
        gce.setAttribute("disposalMethod", "none");
        gce.setAttribute("userInputFlag", "FALSE");
        gce.setAttribute("transparentColorFlag", "FALSE");
        gce.setAttribute("delayTime", delayTime);
        gce.setAttribute("transparentColorIndex", "255");
        root.appendChild(gce);
        IIOMetadataNode aes =
                new IIOMetadataNode("ApplicationExtensions");
        IIOMetadataNode ae =
                new IIOMetadataNode("ApplicationExtension");
        ae.setAttribute("applicationID", "NETSCAPE");
        ae.setAttribute("authenticationCode", "2.0");
        byte[] uo = new byte[]{
            (byte) 0x21, (byte) 0xff, (byte) 0x0b,
            (byte) 'N', (byte) 'E', (byte) 'T', (byte) 'S',
            (byte) 'C', (byte) 'A', (byte) 'P', (byte) 'E',
            (byte) '2', (byte) '.', (byte) '0',
            (byte) 0x03, (byte) 0x01, (byte) 0x00, (byte) 0x00,
            (byte) 0x00
        ae.setUserObject(uo);
        aes.appendChild(ae);
        root.appendChild(aes);
        return root;
    /** Adapted from code via GeogffTitmus on
    http://forums.sun.com/thread.jspa?messageID=9988198 */
    public static File saveAnimate(
            BufferedImage[] frames,
            String name,
            String delayTime) throws Exception {
        File file = null;
        file = new File(name + ".gif");
        Node root = getRootNode(delayTime);
        ImageWriter iw = ImageIO.getImageWritersByFormatName("gif").next();
        ImageOutputStream ios = ImageIO.createImageOutputStream(file);
        iw.setOutput(ios);
        //IIOImage ii = new IIOImage(frames[0], null, null);
        //IIOMetadata im = iw.getDefaultStreamMetadata(null);
        //IIOMetadata im = new AnimatedIIOMetadata();
        //im.setFromTree("gif", root);
        iw.prepareWriteSequence(null);
        for (int i = 0; i < frames.length; i++) {
            BufferedImage src = frames;
ImageWriteParam iwp = iw.getDefaultWriteParam();
IIOMetadata metadata = iw.getDefaultImageMetadata(
new ImageTypeSpecifier(src), null);
System.out.println("IIOMetadata: " + metadata);
metadata.mergeTree(metadata.getNativeMetadataFormatName(), root);
IIOImage ii = new IIOImage(src, null, metadata);
iw.writeToSequence(ii, (ImageWriteParam) null);
iw.endWriteSequence();
ios.close();
return file;
public static void main(String[] args) throws Exception {
// uncomment the other two if you like, but we can
// see it work or fail with just the first and last.
String[] names = {
"bronze",
//"silver",
//"gold",
"platinum"
String pre = "http://forums.sun.com/im/";
String suff = "-star.gif";
BufferedImage[] frames = new BufferedImage[names.length];
for (int ii = 0; ii < names.length; ii++) {
URL url = new URL(pre + names[ii] + suff);
System.out.println(url);
frames[ii] = ImageIO.read(url);
File f = saveAnimate(frames, "animatedstars", "500");
JOptionPane.showMessageDialog(null, new ImageIcon(f.toURI().toURL()));
Desktop.getDesktop().open(f);
ImageInputStream iis = ImageIO.createImageInputStream(f);
//System.out.println("ImageReader: " + ir1);
//System.out.println("IIOMetadata: " + ir1.getStreamMetadata());
Iterator itReaders = ImageIO.getImageReaders(iis);
while (itReaders.hasNext()) {
ImageReader ir = (ImageReader) itReaders.next();
System.out.println("ImageReader: " + ir);
System.out.println("IIOMetadata: " + ir.getStreamMetadata());