Develop Reference

Record and play h.264 video in memory using Jcodec

I am working on a project that requires h.264 video to be written to memory and then read from memory. In other words, using a byte array rather than a File. The only java encoder library that I can find is JCodec.
I am using version 0.2.0 of JCodec's SequenceEncoder8Bit and FrameGrab8Bit classes to read and write to a byte array. The error that I am currently getting is
java.io.IOException: Could not find movie meta information box
at org.jcodec.containers.mp4.demuxer.MP4Demuxer.findMovieBox(MP4Demuxer.java:56)
at org.jcodec.containers.mp4.demuxer.MP4Demuxer.<init>(MP4Demuxer.java:46)
at ....
My code example is as follows:
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.Arrays;
import org.jcodec.api.FrameGrab8Bit;
import org.jcodec.api.JCodecException;
import org.jcodec.api.SequenceEncoder8Bit;
import org.jcodec.common.io.ByteBufferSeekableByteChannel;
import org.jcodec.common.io.SeekableByteChannel;
import org.jcodec.common.model.Picture8Bit;
import org.jcodec.common.model.Rational;
import org.jcodec.scale.AWTUtil;
import org.opencv.core.Mat;
public class Sequence8BitTest {
private static boolean _isDone = false;
public static void main(String[] args) {
byte[] data = writeVideo();
readVideo(data);
}
private static void encodeVideo(SequenceEncoder8Bit encoder, ByteBuffer buffer, int videoSize){
try{//Close Encoder
encoder.finish();
buffer = ByteBuffer.wrap(Arrays.copyOf(buffer.array(), videoSize));
}catch(IOException e){
e.printStackTrace();
}
}
private static BufferedImage matToBufferedImage(Mat in) throws IOException {
byte[] data = new byte[in.width() * in.height() * (int)in.elemSize()];
int type;
BufferedImage out;
in.get(0, 0, data);
if(in.channels() == 1){
type = BufferedImage.TYPE_BYTE_GRAY;
}
else{
type = BufferedImage.TYPE_3BYTE_BGR;
}
out = new BufferedImage(in.width(), in.height(), type);
out.getRaster().setDataElements(0, 0, in.width(), in.height(), data);
return out;
}
private static BufferedImage readImage(FrameGrab8Bit grabber) {
Picture8Bit pic = null;
try {
pic = grabber.getNativeFrame();
} catch (IOException e) {
e.printStackTrace();
return null;
}
return AWTUtil.toBufferedImage8Bit(pic);
}
private static void readVideo(byte[] data){
FrameGrab8Bit grabber = null;
BufferedImage img;
ByteBuffer buffer;
SeekableByteChannel channel;
buffer = ByteBuffer.wrap(data);
channel = new ByteBufferSeekableByteChannel(buffer);
try {
grabber = FrameGrab8Bit.createFrameGrab8Bit(channel);
while((img = readImage(grabber)) != null){
//display Image
}
channel.close();
} catch (IOException | JCodecException e) {
e.printStackTrace();
System.exit(-1);
}
}
private static void writeImage(Mat mat, SequenceEncoder8Bit encoder){
try{//Mat -> BufferedImage -> Picture8Bit
BufferedImage img = matToBufferedImage(mat);
Picture8Bit pic = AWTUtil.fromBufferedImageRGB8Bit(img);//this is the
encoder.encodeNativeFrame(pic); //only constructor that won't crash
}catch(Exception e){
e.printStackTrace();
}
}
public static byte[] writeVideo(){
int fps = 25;
int videoSize = 300_000;//allocated for buffer --> think max size
ByteBuffer buffer = ByteBuffer.allocate(videoSize);
Mat mat = new Mat();
SeekableByteChannel channel = new ByteBufferSeekableByteChannel(buffer);
SequenceEncoder8Bit enc = null;
try {// new SequenceEncoder..
enc = new SequenceEncoder8Bit(channel, new Rational(fps, 1));
enc.getEncoder().setKeyInterval(fps);
while(!_isDone){//Here, grabbing mat frames from camera using JavaCV
writeImage(mat, enc);
}
encodeVideo(enc, buffer, (int)channel.position());
} catch (IOException e1) {
e1.printStackTrace();
}
return buffer.array();
}
}
I looked into the code base and the call to SequenceEncoder8Bit.finish() does write a header to the buffer. Not sure why I can't get the metadata. Anyone out their familiar with this stuff?

Writing a BufferedImage cache and save it to disk

I'm developing a java application in which I load some long lists containing images (downloaded from web), so I added a quick HashMap<String,BufferedImage> as a cache, to avoid redownloading the same image multiple times.
This works fine and the application is way faster, but it would be nice to let this cache persist through the various sessions, so I changed my cache to be serialized.
BufferedImage is not Serializable, so I had to wrote my custom methods.
My file structure should be something like:
(int) number of elements
[(URL) image's key
(Object) image written using ImageIO] n times
While file saving seems fine (at least I have no exceptions), when I try to load the URL it throws java.io.OptionalDataException with length = 4 and I don't understand why. The first iteration goes fine, but I have this exception as soon as I try to load the second URL, so I suspect that there's something wrong in the way I load the first image.
Here's the full code :
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Map.Entry;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.imageio.ImageIO;
public class PicturesCache {
private static HashMap<String, BufferedImage> picturesCache;
private static final String cacheDiskLocation = "pictures_cache.map";
private static void writeCache(ObjectOutputStream oos, HashMap<String, BufferedImage> data) throws IOException {
// Number of saved elements
oos.writeInt(data.size());
// Let's write (url, image) for each entry in the cache
for (Entry<String, BufferedImage> entry : data.entrySet()) {
oos.writeObject(new URL(entry.getKey()));
ImageIO.write(entry.getValue(), "png", oos);
}
}
private static HashMap<String, BufferedImage> readCache(ObjectInputStream ois) throws IOException, ClassNotFoundException {
// Number of saved elements
int size = ois.readInt();
// Cache
HashMap<String, BufferedImage> result = new HashMap<>(size);
// Let's read (url, image) and add them to cache
for (int i = 0; i < size; i++) {
String url = ((URL) ois.readObject()).toString(); // EXCEPTION HERE
BufferedImage image = ImageIO.read(ois);
result.put(url, image);
}
return result;
}
public static void loadCache() {
picturesCache = new HashMap<>();
File file = new File(cacheDiskLocation);
if (file.isFile()) {
FileInputStream fis = null;
ObjectInputStream ois = null;
try {
fis = new FileInputStream(file);
ois = new ObjectInputStream(fis);
picturesCache = readCache(ois);
} catch (IOException | ClassNotFoundException ex) {
Logger.getLogger(PicturesCache.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
ois.close();
fis.close();
} catch (IOException ex) {
Logger.getLogger(PicturesCache.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
System.out.println("Cache loaded with " + picturesCache.size() + " elements");
}
public static void saveCache() {
File file = new File(cacheDiskLocation);
FileOutputStream fos = null;
ObjectOutputStream oos = null;
try {
if (file.isFile()) {
file.delete();
}
file.createNewFile();
fos = new FileOutputStream(file);
oos = new ObjectOutputStream(fos);
writeCache(oos, picturesCache);
} catch (IOException ex) {
Logger.getLogger(PicturesCache.class.getName()).log(Level.SEVERE, null, ex);
} finally {
try {
System.out.println("Cache saved with " + picturesCache.size() + " elements");
oos.close();
fos.close();
} catch (IOException ex) {
Logger.getLogger(PicturesCache.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
public static boolean contains(String url) {
return picturesCache.containsKey(url);
}
public static BufferedImage get(String url) {
return picturesCache.get(url);
}
public static void put(String url, BufferedImage image) {
picturesCache.put(url, image);
}
}

The error occurs because ImageIO.read(...) doesn't read all the data that was written using ImageIO.write(...). You can write the image to the ObjectOutputStread as a byte[]. For example:
private static void writeCache(ObjectOutputStream oos,
HashMap<String, BufferedImage> data) throws IOException {
// Number of saved elements
oos.writeInt(data.size());
// Let's write (url, image) for each entry in the cache
for (Entry<String, BufferedImage> entry : data.entrySet()) {
oos.writeObject(new URL(entry.getKey()));
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(entry.getValue(), "jpg", baos);
byte[] bytes = baos.toByteArray();
oos.writeObject(bytes);
}
}
private static HashMap<String, BufferedImage> readCache(
ObjectInputStream ois) throws IOException, ClassNotFoundException {
// Number of saved elements
int size = ois.readInt();
// Cache
HashMap<String, BufferedImage> result = new HashMap<>(size);
// Let's read (url, image) and add them to cache
for (int i = 0; i < size; i++) {
String url = ((URL) ois.readObject()).toString(); // EXCEPTION HERE
ByteArrayInputStream bais = new ByteArrayInputStream(
(byte[]) ois.readObject());
BufferedImage image = ImageIO.read(bais);
result.put(url, image);
}
return result;
}

Serialization of an arraylist which contains another arraylist

my research on google-search and stackoverflow regarding this problem didn't resolve it.
i'd like to show you a snipped of my Datastructure:
there's a class, called "SequenceHolder" => this one carries an:
ArrayList<SequenceData> data;
within the Sequenceholder, there is a function to call the serialization:
public void writeSequenceList() throws FileNotFoundException, IOException {
FileOutputStream fout = new FileOutputStream(path);
ObjectOutputStream oout = new ObjectOutputStream(fout);
oout.writeObject(data);
oout.close();
fout.close();
}
The class SequenceObject has following fields: (this one is on the top, where i start the serialization)
private ArrayList<SequenceModel> recordedSequenceData;
private String sequenceUrl;
while the SequenceModel is defined like this:
private Object sequenceRawData;
private boolean isProcessedByRequest;
The sequenceRawdata objects are basically two other classes (containing Strings only)!
every class of this "trail" implements the interface "Serializable".
this is the deserialization:
public ArrayList<SequenceData> loadSequenceList() throws FileNotFoundException, IOException, ClassNotFoundException {
FileInputStream fileIn = new FileInputStream(path);
ObjectInputStream in = new ObjectInputStream(fileIn);
this.data = (ArrayList<SequenceData>) in.readObject();
in.close();
fileIn.close();
return data; // load from de-serialization
}
after a deserialization of the SequenceObject, i'll only retrieve the "sequenceUrl", but no recordedSequenceData.
Is there a trick to do this?!
It came just up to my mind, to extend some classes with the ObjectOutputStream and call the writingprocess with "this" explicitly in every class - but yeah, i am not sure if thats a good idead.

What do you mean by "The sequenceRawdata objects are basically two other classes (containing Strings only)!" because when I try to run the same program :
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.ArrayList;
class SequenceModel implements Serializable
{
public SequenceModel(Object a, boolean b)
{
sequenceRawData = a;
isProcessedByRequest = b;
}
public String toString()
{
return (String)sequenceRawData + isProcessedByRequest + " SeqModel ";
}
private Object sequenceRawData;
private boolean isProcessedByRequest;
}
class SequenceData implements Serializable
{
public SequenceData(ArrayList<SequenceModel> a, String b)
{
recordedSequenceData = a;
sequenceUrl = b;
}
public String toString()
{
return recordedSequenceData + sequenceUrl + " SeqData ";
}
private ArrayList<SequenceModel> recordedSequenceData;
private String sequenceUrl;
}
class SequenceHolder implements Serializable
{
ArrayList<SequenceData> data;
public String toString()
{
return data + " SeqHol ";
}
public SequenceHolder(ArrayList<SequenceData> a)
{
data = a;
}
public void writeSequenceList() throws FileNotFoundException, IOException {
FileOutputStream fout = new FileOutputStream(Test.file);
ObjectOutputStream oout = new ObjectOutputStream(fout);
oout.writeObject(data);
oout.close();
fout.close();
}
public ArrayList<SequenceData> loadSequenceList() throws FileNotFoundException, IOException, ClassNotFoundException {
FileInputStream fileIn = new FileInputStream(Test.file);
ObjectInputStream in = new ObjectInputStream(fileIn);
this.data = (ArrayList<SequenceData>) in.readObject();
in.close();
fileIn.close();
return data; // load from de-serialization
}
}
public class Test
{
public static File file = new File("abc.txt");
public static void main(String[] args)
{
SequenceModel obj = new SequenceModel("abc", false);
ArrayList list = new ArrayList(); list.add(obj);
SequenceData obh = new SequenceData(list, "str");
ArrayList l2 = new ArrayList();
l2.add(obh);
SequenceHolder obi = new SequenceHolder(l2);
try {
obi.writeSequenceList();
System.out.println(obi.loadSequenceList());
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
it is able to serialize and deserialize both and there is no problem.
Output it is printing is : [[abcfalse SeqModel ]str SeqData ] which includes everything as desired.
Please let me know if I am missing anything.

Saving internet icon then re-opening causes EOF with image4j

I'm currently working on a project where I'm attempting to download a .ico file, but for some strange reason, I can't seem to open it programmatically once downloaded. I can however, open the image saved using any image editor or viewer. My code:
public static BufferedImage parseImageLocal(String url) throws IOException {
if (url.endsWith(".ico")) {
return ICODecoder.read(new File(url)).get(0);
} else if (url.endsWith(".bmp")) {
return BMPDecoder.read(new File(url));
} else {
return ImageIO.read(new File(url));
}
}
public static void saveImage(BufferedImage img, String path)
throws IOException {
File outputfile = new File(path.replace("http://", ""));
File parent = outputfile.getParentFile();
parent.mkdir();
if (!outputfile.exists()) {
outputfile.createNewFile();
}
if (path.endsWith(".ico")) {
ICOEncoder.write(img, outputfile);
} else if (path.endsWith(".bmp")) {
BMPEncoder.write(img, outputfile);
} else {
ImageIO.write(img, "png", outputfile);
}
}
And this is how i download images from the internet:
public static BufferedImage parseImage(String url) throws IOException {
URL dest = new URL(url);
if (url.endsWith(".ico")) {
return ICODecoder.read(dest.openStream()).get(0);
} else if (url.endsWith(".bmp")) {
return BMPDecoder.read(dest.openStream());
} else {
return ImageIO.read(dest);
}
}
The error is on this line:
return ICODecoder.read(new File(url)).get(0);

It "seems" that you are trying to download the icon from the internet, but you are trying to treat the URL as a File.
Basically, this isn't going to be possible, File won't be able to resolve to an actual physical file.
Instead, you should be using ICODecoder#read(InputStream) and URL#openStream
Something more like...
BufferedImage img = null;
InputStream is = null;
try {
// url begin an instance of java.net.URL
is = url.openStream();
img = ICODecoder.read(is);
} finally {
try {
is.close();
} catch (Exception exp) {
}
}
return img;
Updated with example
A web resource is not a File, you can not access it as if they were, instead, you need to use the classes designed for interacting with the internet/network.
For example...
import java.awt.EventQueue;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.List;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import net.sf.image4j.codec.ico.ICODecoder;
public class ReadFavicon {
public static void main(String[] args) {
new ReadFavicon();
}
public ReadFavicon() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
try {
BufferedImage img = readIcon(new URL("https://secure.gravatar.com/favicon.ico"));
JOptionPane.showMessageDialog(null, "My FAVICON", "Icon", JOptionPane.PLAIN_MESSAGE, new ImageIcon(img));
} catch (IOException ex) {
ex.printStackTrace();
}
}
});
}
public BufferedImage readIcon(URL url) throws IOException {
BufferedImage img = null;
InputStream is = null;
try {
// url begin an instance of java.net.URL
is = url.openStream();
List<BufferedImage> imgs = ICODecoder.read(is);
img = imgs != null ? imgs.size() > 0 ? imgs.get(0) : null : null;
} finally {
try {
is.close();
} catch (Exception exp) {
}
}
return img;
}
}
Update with some more ideas
Now. I could be wrong, but when I ran your code, I ran into a serious of problems with the paths...
Let's assume the original url/path is https://secure.gravatar.com/favicon.ico, when you save the image, you do something like...
File outputfile = new File(path.replace("http://", ""));
File parent = outputfile.getParentFile();
parent.mkdir();
With our original path, this would result in a outputfile of https://secure.gravatar.com/favicon.ico, which is obviously wrong...
We can correct for this by using path.replace("https://", "") as well...
path = path.replace("http://", "");
path = path.replace("https://", "");
File outputfile = new File(path);
File parent = outputfile.getParentFile();
parent.mkdir();
Now, this results in a outputfile of secure.gravatar.com/favicon.ico. I become a little unstuck, as I'm not sure if this is what you want...but it does work for me...
Now, when you read the file, you do something like this...
public static BufferedImage parseImage(String url) throws IOException {
URL dest = new URL(url);
if (url.endsWith(".ico")) {
return ICODecoder.read(dest.openStream()).get(0);
} else if (url.endsWith(".bmp")) {
return BMPDecoder.read(dest.openStream());
} else {
return ImageIO.read(dest);
}
}
Now, with no evidence to the contray, I have to assume the url has not changed and is still https://secure.gravatar.com/favicon.ico...this means that new File("https://secure.gravatar.com/favicon.ico") will produce an invalid file reference
So, again, I parsed the input...
url = url.replace("https://", "");
url = url.replace("http://", "");
File outputfile = new File(url);
String parentPath = outputfile.getParent();
String name = outputfile.getName();
url = parentPath + File.separator + name;
Which produces secure.gravatar.com\favicon.ico
This all downloaded, wrote and read without error.

What are the errors of this Java code?

package example;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.lang.Object;
public static Object copy(Object oldObj) {
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
public class mytest {
public static void main(String[] args) throws IOException {
clone
}
}
For above code, it wants to show the deep copy of Java. But myeclipse reports some errors. But I don't know what is wrong with it?
Could anyone please help to point them out?
Changed the code according to your suggestion.
package example;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.Object;
class Utils {
public static Object copy(Object oldObj) {
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
}
public class mytest {
public static void main(String[] args) throws IOException {
Object clonedObject = Utils.copy(new Object());
clonedObject.notifyAll();
}
}
Further:
Thank you all!
I modifeid the code like above, it becomes better but still cannot run normally.
The new error message is below:
Any new suggestion?

You can't have floating methods in Java. Everything must be a member of a class. In this instance, a dummy class with only static methods called Utils would be common practice.
e.g.
public class Utils {
// Static methods go here
public static Object copy(Object oldObj) {
// etc
}
}
Then you can call it like so:
public class mytest {
public static void main(String[] args) throws IOException {
Object clonedObject = Utils.copy(new Object());
// etc
}
}

Here are the following steps to solve your errors:
Make a package inside a Project(Specific Name)
Inside a created package make a name MyTest.
Write or copy the method into that class which has been created
above.
To Run the Program Make one main Method any call it by there name if
it is static.
If your method is not static make a object of the class and call by
that object of the class.
It will solve your Error & also run your program...
Note: Try to put finally block to free the resources like object, ByteArrayOutputStream & ObjectStream etc.... It will increase your performance of the program.

You need to put a method into a class.
public class SomeClass{
public static Object copy(Object oldObj) {
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
And you can use it as:
public class mytest {
public static void main(String[] args) throws IOException {
Object object = Someclass.copy(someObject);
}
}

You can't declare methods (even static ones) outside of a class in Java. You would have to put everything (except the imports) inside a class.
You'll need something like:
public class YourClass {
public static Object copy(Object oldObj) {
...
}
}

The method public static Object copy(Object oldObj) isn't located in a class. That's why you are getting the error.

You must add a class named mytest as the 'top level scope' of this file, nest all other methods in it.
class mytest {
public static Object copy(Object oldObj) {
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
public class mytest {
public static void main(String[] args) throws IOException {
clone
}
}
}
As a side note, you should rename the class name (and file name) to MyTest and MyTest.java - to match the java coding convention.

You should put your method in a class, preferably called mytest since it's the name of the file, declared like
public class mytest {
//Your method here
}
Also note that the naming convention in Java is to have class names starting with a capital letter, so it would be MyTest, and your file should be renamed to reflect that.

Try
public class MyTest {
public static Object copy(Object oldObj) {
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
public static void main(String[] args) throws IOException {
clone
}
}
There are no methods who do not belong to a class (like a JavaScript-Function).
Static means that the method does belong to the class and not to an instance of the class as a non static method would do

You can't write methods outside the class. Put your method #copy inside the class. like this:
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
public class mytest
{
public static void main(String[] args) throws IOException
{
// Now you can use your method here
}
public static Object copy(Object oldObj)
{
Object obj = null;
try {
// Write the object out to a byte array
ByteArrayOutputStream bos = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(bos);
out.writeObject(oldObj);
out.flush();
out.close();
// Retrieve an input stream from the byte array and read
// a copy of the object back in.
ByteArrayInputStream bis = new ByteArrayInputStream(bos.toByteArray());
ObjectInputStream in = new ObjectInputStream(bis);
obj = in.readObject();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException cnfe) {
cnfe.printStackTrace();
}
return obj;
}
}

Where is the class here? these method should contain a class.
Your java class should looks like this
package name;
imports;
public class MyClass{
public void myMethod(){
}
}