Java Custom Class Loader - java

Any ideas why I am getting this error? (Yes, I looked up the error, and still haven't found a solution)
My error:
Exception in thread "main" java.lang.ClassFormatError: Truncated class file
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(Unknown Source)
at java.lang.ClassLoader.defineClass(Unknown Source)
at org.fellixombc.mysql.util.MysqlClassLoader.findClass(MysqlClassLoader.java:22)
at org.fellixombc.mysql.util.MysqlClassLoader.loadClass(MysqlClassLoader.java:14)
at org.fellixombc.mysql.Main.main(Main.java:9)
Files:
Main.java
package org.fellixombc.mysql;
import org.fellixombc.mysql.util.MysqlClassLoader;
public class Main {
public static void main(String[] args) {
MysqlClassLoader mcl = new MysqlClassLoader();
try {
mcl.loadClass("org.fellixombc.mysql.net.Client");
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
}
}
Client.java:
package org.fellixombc.mysql.net;
public class Client {
public Client() {
System.out.println("Hello!");
}
}
MysqlClassLoder.java:
package org.fellixombc.mysql.util;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
public class MysqlClassLoader extends ClassLoader {
public MysqlClassLoader() {
super(MysqlClassLoader.class.getClassLoader());
}
#Override
public Class<?> loadClass(String className) throws ClassNotFoundException {
return findClass(className);
}
#Override
public Class<?> findClass(String className) throws ClassNotFoundException {
byte[] b = null;
try {
b = loadClassData(className);
Class c = defineClass(className, b, 0, b.length);
if(c != null)
return c;
return super.findClass(className);
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private byte[] loadClassData(String className) throws IOException {
int size = className.length();
byte buff[] = new byte[size];
// Open the file
FileInputStream fis = new FileInputStream("bin/" + className.replace('.', File.separatorChar) + ".class");
fis.available();
fis.read(buff);
fis.close();
return buff;
}
}

Yes, you're reading at most a byte count equal to the number of characters in the filename. Instead, you need to read the whole file. Here's one method, using readFully as you suggested.
File f = new File("bin/" + className.replace('.', File.separatorChar) + ".class");
DataInputStream is = new DataInputStream(new FileInputStream(f));
int len = (int)f.length();
byte[] buff = new byte[len];
is.readFully(buff);
is.close();
return buff;
Since you're not handling built-in classes like Object, I think you need to catch the FileNotFoundException from loadClassData in your findClass, then call super.findClass. E.g.:
try {
try {
b = loadClassData(className);
}
catch(FileNotFoundException fnf) {
return super.findClass(className);
}
Class c = defineClass(className, b, 0, b.length);
if(c != null)
return c;
return super.findClass(className);
} catch (IOException e) {
e.printStackTrace();
}
return null;

You are reading only N bytes (N=length of class name) from the .class file into the buffer (in loadClassData) before returning it.
You need to read the contents of the entire class before you return the buffer for the class to be properly defined.

Related

How to code coverage a IOException catch JUnit5

Have not been able to write a test that covers the catch in here:
public class ServiceToTest {
public void unzip(byte[] zipFile) {
try (ZipInputStream zipInputStream = new ZipInputStream(new ByteArrayInputStream(zipFile))) {
ZipEntry entry;
while ((entry = zipInputStream.getNextEntry()) != null) {
byte[] buffer = new byte[1024];
int len;
try (var file = new ByteArrayOutputStream(buffer.length)) {
while ((len = zipInputStream.read(buffer)) > 0) {
file.write(buffer, 0, len);
}
System.out.println(entry.getName());
}
}
} catch (IOException e) {
System.out.println(e.getMessage());
// some logic or rethrow the exception
}
}
}
Have tried for a while with the help of Mockito but nothing seems to work with this one, I was thinking on mocking the ZipInputStream and throw a IOException when it tries to getNextEntry() or somehow throw the IOException at any moment so I can coverage that catch, but since everything is inside the method I do not know how could I mock something inside it? Another option was to change the IOException to Exception, and I can cause that catch by passing a null zipFile in my test, but that does not seem like the right way, any ideas?
Also the method does more stuff but I let it here as simple as I could so that we can focus on covering the catch
I would go with extracting the part which could cause IOException and override that in a test implementation to invoke the Exception block code
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
public class ServiceToTest {
public void unzip(byte[] zipFile) {
try (ZipInputStream zipInputStream = new ZipInputStream(new ByteArrayInputStream(zipFile))) {
writeToFile(zipInputStream);
} catch (IOException e) {
System.out.println(e.getMessage());
}
}
protected void writeToFile(ZipInputStream zipInputStream) throws IOException {
ZipEntry entry;
while ((entry = zipInputStream.getNextEntry()) != null) {
byte[] buffer = new byte[1024];
int len;
try (ByteArrayOutputStream file = new ByteArrayOutputStream(buffer.length)) {
while ((len = zipInputStream.read(buffer)) > 0) {
file.write(buffer, 0, len);
}
System.out.println(entry.getName());
}
}
}
}
The test should something be like
import org.junit.jupiter.api.Test;
import java.io.File;
import java.io.IOException;
import java.util.zip.ZipInputStream;
class ServiceTest {
#Test
public void shouldUnzip() {
ServiceToTest serviceToTest = new ServiceToTest();
serviceToTest.unzip(new File("yourFilePath").toString().getBytes());
//Assert happy path
}
#Test
public void shouldThrowIOException() {
ServiceToTest serviceToTest = new ServiceToTestChild();
serviceToTest.unzip(new File("yourFilePath").toString().getBytes());
//Assert exception path
}
private class ServiceToTestChild extends ServiceToTest {
#Override
protected void writeToFile(ZipInputStream zipInputStream) throws IOException {
throw new IOException();
}
}
}

Java DecriptionInfo on Word DocX

I'm pulling my hair out as I cannot get the samples to work - hopefully someone can help..
I would like to DETECT if a docx and a doc file is password protected/encrypted. I have seen this posted in a few places but I cannot get it work - it doesnt throw an exception. Can someone see what I am doing wrong. Note I only need to detect the password..i dont want to open the document.
String fileLocation = "C:/myfile.docx";
File file = new File(fileLocation);
FileInputStream fis = new FileInputStream(file.getAbsolutePath());
POIFSFileSystem pfis = new POIFSFileSystem(fis);
try{
EncryptionInfo info = new EncryptionInfo(pfis);
EncryptionMode mode = info.getEncryptionMode();
Decryptor d = Decryptor.getInstance(info);
//Try and open it
if(!d.verifyPassword(Decryptor.DEFAULT_PASSWORD))
{
//file is encrypted
}
}
catch(GeneralSecurityException gse)
{
//file is encrypted
}
catch(EncryptedDocumentException edc)
{
//file is encrypted
}
I haven't elaborated much to get the code smaller, but I've simply taken one of the factory classes - like SlideShowFactory - and modified it for H/XWPF. As H/XWPF hasn't got a common interface on the document level (as of now), the quick&dirty approach is to return an Object.
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;
import org.apache.poi.EncryptedDocumentException;
import org.apache.poi.hssf.record.crypto.Biff8EncryptionKey;
import org.apache.poi.hwpf.HWPFDocument;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackageAccess;
import org.apache.poi.poifs.crypt.Decryptor;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.DocumentFactoryHelper;
import org.apache.poi.poifs.filesystem.NPOIFSFileSystem;
import org.apache.poi.poifs.filesystem.OfficeXmlFileException;
import org.apache.poi.util.IOUtils;
import org.apache.poi.xwpf.usermodel.XWPFDocument;
public class EncDetect {
public static void main(String[] args) {
String dir = "/home/kiwiwings/project/poi/poi/test-data";
String[] files = {
"document/bug53475-password-is-solrcell.docx",
"document/password_tika_binaryrc4.doc",
"document/58067.docx",
"document/58804.doc"
};
for (String f : files) {
try {
DocumentFactory.create(new File(dir, f));
System.out.println(f + " not encrypted");
} catch (EncryptedDocumentException e) {
System.out.println(f + " is encrypted");
} catch (Exception e) {
System.out.println(f + " " +e.getMessage());
}
}
}
static class DocumentFactory {
public static Object create(NPOIFSFileSystem fs) throws IOException {
return create(fs, null);
}
public static Object create(final NPOIFSFileSystem fs, String password) throws IOException {
DirectoryNode root = fs.getRoot();
// Encrypted OOXML files go inside OLE2 containers, is this one?
if (root.hasEntry(Decryptor.DEFAULT_POIFS_ENTRY)) {
InputStream stream = null;
try {
stream = DocumentFactoryHelper.getDecryptedStream(fs, password);
return createXWPFDocument(stream);
} finally {
IOUtils.closeQuietly(stream);
}
}
// If we get here, it isn't an encrypted XWPF file
// So, treat it as a regular HWPF one
boolean passwordSet = false;
if (password != null) {
Biff8EncryptionKey.setCurrentUserPassword(password);
passwordSet = true;
}
try {
return createHWPFDocument(fs);
} finally {
if (passwordSet) {
Biff8EncryptionKey.setCurrentUserPassword(null);
}
}
}
public static Object create(InputStream inp) throws IOException, EncryptedDocumentException {
return create(inp, null);
}
public static Object create(InputStream inp, String password) throws IOException, EncryptedDocumentException {
// If clearly doesn't do mark/reset, wrap up
if (! inp.markSupported()) {
inp = new PushbackInputStream(inp, 8);
}
// Ensure that there is at least some data there
byte[] header8 = IOUtils.peekFirst8Bytes(inp);
// Try to create
if (NPOIFSFileSystem.hasPOIFSHeader(header8)) {
NPOIFSFileSystem fs = new NPOIFSFileSystem(inp);
return create(fs, password);
}
if (DocumentFactoryHelper.hasOOXMLHeader(inp)) {
return createXWPFDocument(inp);
}
throw new IllegalArgumentException("Your InputStream was neither an OLE2 stream, nor an OOXML stream");
}
public static Object create(File file) throws IOException, EncryptedDocumentException {
return create(file, null);
}
public static Object create(File file, String password) throws IOException, EncryptedDocumentException {
return create(file, password, false);
}
public static Object create(File file, String password, boolean readOnly) throws IOException, EncryptedDocumentException {
if (!file.exists()) {
throw new FileNotFoundException(file.toString());
}
NPOIFSFileSystem fs = null;
try {
fs = new NPOIFSFileSystem(file, readOnly);
return create(fs, password);
} catch(OfficeXmlFileException e) {
IOUtils.closeQuietly(fs);
return createXWPFDocument(file, readOnly);
} catch(RuntimeException e) {
IOUtils.closeQuietly(fs);
throw e;
}
}
protected static Object createHWPFDocument(NPOIFSFileSystem fs) throws IOException, EncryptedDocumentException {
return new HWPFDocument(fs.getRoot());
}
protected static Object createXWPFDocument(InputStream stream) throws IOException, EncryptedDocumentException {
return new XWPFDocument(stream);
}
protected static Object createXWPFDocument(File file, boolean readOnly) throws IOException, EncryptedDocumentException {
try {
OPCPackage pkg = OPCPackage.open(file, readOnly ? PackageAccess.READ : PackageAccess.READ_WRITE);
return new XWPFDocument(pkg);
} catch (InvalidFormatException e) {
throw new IOException(e);
}
}
}
}

Copy files from the list using threads

I'm working on a project that copies files with four threads.
I create List and store in there name of files to copy.
I want to use this 4 thread to work together, but I don't really get it how make it happend.
public class CopyingFiles implements Runnable
{
static File source = new File("C:\\test\\1\\");
static File dest = new File("C:\\test\\2\\");
#Override
public void run()
{
try
{
CopyingFromList(source, dest);
}
catch (IOException e)
{
e.printStackTrace();
}
catch (InterruptedException e)
{
e.printStackTrace();
}
}
public static void CopyFile(File sourceFile, File destination) throws IOException
{
InputStream inputStream = null;
OutputStream outputStream = null;
try {
inputStream = new FileInputStream(sourceFile);
outputStream = new FileOutputStream(destination);
byte[] buffer = new byte[1024];
int length;
while ((length = inputStream.read(buffer)) > 0)
{
outputStream.write(buffer, 0 ,length);
}
} finally {
if(inputStream != null)
{
inputStream.close();
}
if(inputStream != null)
{
outputStream.close();
}
}
}
public static void CopyingFromList(File source, File dest) throws IOException, InterruptedException
{
List<String> fileList = FilesList.CreateFilesList(source);
for(String file : fileList)
{
System.out.println(Thread.currentThread().getName() + " > " + FilesList.DestinationOfFile(source) + file + " > " + FilesList.DestinationOfFile(dest) + file );
CopyFile(new File(FilesList.DestinationOfFile(source) + file), new File(FilesList.DestinationOfFile(dest) + file));
}
}
}
AND SECOND CLASS
public class FilesList
{
static File source = new File("C:\\test\\1\\");
static File source1 = new File("C:\\test\\3\\");
static File dest = new File("C:\\test\\2\\");
static File dest1 = new File("C:\\test\\4\\");
public static List<String> CreateFilesList(File source) throws InterruptedException, IOException
{
List<String> fileList = new ArrayList<>(Arrays.asList(source.list()));
return fileList;
}
public static String DestinationOfFile(File source)
{
return new String(source + "\\");
}
public static void PrintWholeList(File source) throws IOException, InterruptedException
{
List<String> fileList = CreateFilesList(source);
for(String file : fileList)
{
System.out.println(DestinationOfFile(source) + file);
}
}
public static void main(String []args) throws IOException, InterruptedException
{ /*
//CopyingFiles.CopyFile(new File(source+"\\file1.txt"), new File(dest+"\\file1.txt"));
//CopyingFiles.CopyingFromList(source,dest);
CopyingFiles t1 = new CopyingFiles();
CopyingFiles t2 = new CopyingFiles();
CopyingFiles t3 = new CopyingFiles();
CopyingFiles t4 = new CopyingFiles();
t1.start();
t2.start();
t3.start();
t4.start();
*/
ExecutorService executorService = Executors.newFixedThreadPool(5);
System.out.println(Thread.activeCount());
executorService.submit(() -> {
try
{
CopyingFiles.CopyingFromList(source,dest);
}
catch (IOException e)
{
e.printStackTrace();
}
catch (InterruptedException e)
{
e.printStackTrace();
}
finally
{
executorService.shutdown();
}
});
}
}
Could anyone help me,or show some other way to solve my problem.
I don't actually get what the problem is. This one works for me (and it is almost your program, just cleaned up a bit):
package multicp;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import static java.nio.file.StandardCopyOption.COPY_ATTRIBUTES;
/**
* Copy files using threads.
*/
public class Multicp {
public static void main(String[] args) {
// List of source/dest pairs ("tasks")
List<CopierCallable<Void>> opsList = new ArrayList<>();
opsList.add(new CopierCallable<>(Paths.get("f1src.dat"), Paths.get("f1dest.dat")));
opsList.add(new CopierCallable<>(Paths.get("f2src.dat"), Paths.get("f2dest.dat")));
opsList.add(new CopierCallable<>(Paths.get("f3src.dat"), Paths.get("f3dest.dat")));
opsList.add(new CopierCallable<>(Paths.get("f4src.dat"), Paths.get("f4dest.dat")));
ExecutorService execSvc = Executors.newFixedThreadPool(2); // 4 in your case. 2 is just for testing
try {
execSvc.invokeAll(opsList);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
execSvc.shutdown();
}
}
}
/**
* Performs actual copying from one source to one destination.
*/
class CopierCallable<Void> implements Callable<Void> {
private Path pathFrom;
private Path pathTo;
public CopierCallable(Path pathFrom, Path pathTo) {
this.pathFrom = pathFrom;
this.pathTo = pathTo;
}
#Override
public Void call() {
try {
// REPLACE_EXISTING is destructive, uncomment at your own risk
Files.copy(pathFrom, pathTo, COPY_ATTRIBUTES /*, REPLACE_EXISTING*/);
System.out.println(pathFrom + " copied");
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
I can see files being copied simultaneously in groups (by 2 for testing; replace with 4, but it would make initialization code larger for no profit).

Java : InputStream to Multi-part file conversion, result file is empty

I am working on a Java application in which I am trying to create a Multipart file out of downloaded InputStream. Unfortunately, it is not working and the Multipart file is empty. I checked the size of savedFile on disk before copying it to Multipart, and it has correct size, attributes, content.
What am I doing wrong in the conversion, there is no stacktrace, as I am catching it.
Code :
// InputStream contains file data.
byte[] bytes = IOUtils.toByteArray(inputStream);
File file = new File(msg + "temp");
if (file.exists() && file.isDirectory()) {
OutputStream outputStream = new FileOutputStream(new File(msg + "temp" + "/" +
groupAttachments.getFileName()));
outputStream.write(bytes);
outputStream.close();
}
java.io.File savedFile = new java.io.File(msg + "temp" + "/" +
groupAttachments.getFileName());
DiskFileItem fileItem = new DiskFileItem("file", "text/plain", false,
savedFile.getName(), (int) savedFile.length(), savedFile.getParentFile());
fileItem.getOutputStream();
MultipartFile multipartFile = new CommonsMultipartFile(fileItem);
System.out.println("Saved file size is "+savedFile.length());
if (multipartFile.isEmpty()) {
System.out.println("Dropbox uploaded multipart file is empty");
} else {
System.out.println("Multipart file is not empty.");
}
this.dropboxTask.insertFile(multipartFile, "",
savedPersonalNoteObject.getNoteid(), (long) 0, true);
Path path = Paths.get(msg + "temp" + "/" + groupAttachments.getFileName());
Console output :
Multipart file is not empty
Bytes are not null
File path is /My Group
Input stream is not null
Saved file size is 4765
Dropbox uploaded multipart file is empty
Multipart file is empty
Bytes are not null
What am I doing wrong in the conversion? Any help would be nice. Thanks a lot.
The DiskFileItem uses a DeferredFileOutputStream which uses an in-memory byte-array that is only filled when bytes are actually transferred.
Since files are used directly and no bytes are actually copied,
the byte-array is never filled. See for yourself in the source code:
Source code CommonsMultipartFile
Source code DiskFileItem
Source code DeferredFileOutputStream
So, instead of just calling fileItem.getOutputStream();, transfer the bytes to fill the in-memory byte-array:
try (OutputStream out = fileItem.getOutputStream();
InputStream in = Files.newInputStream(file.toPath())) {
IOUtils.copy(in, dfos);
}
and then the tranferTo call will work.
This appears to be a bit cumbersome for just moving a file: CommonsMultipartFile only calls fileItem.write((File)dest) in the transferTo method.
Below are two test cases, one using the DiskFileItem and one using the LocalFileItem. The code for LocalFileItem is shown further below.
I used dependencies org.springframework:spring-web:4.2.2.RELEASE, commons-fileupload:commons-fileupload:1.3.1 and junit:junit:4.12
Test class CommonMp:
import static org.junit.Assert.*;
import java.io.*;
import java.nio.charset.*;
import java.nio.file.*;
import org.apache.commons.fileupload.disk.DiskFileItem;
import org.apache.commons.io.IOUtils;
import org.junit.Test;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
public class CommonMp {
private final Charset CS = StandardCharsets.UTF_8;
#Test
public void testLocalMp() {
Path testInputFile = null, testOutputFile = null;
try {
testInputFile = prepareInputFile();
LocalFileItem lfi = new LocalFileItem(testInputFile);
CommonsMultipartFile cmf = new CommonsMultipartFile(lfi);
System.out.println("Empty: " + cmf.isEmpty());
testOutputFile = testInputFile.getParent().resolve("testMpOutput.txt");
cmf.transferTo(testOutputFile.toFile());
System.out.println("Size: " + cmf.getSize());
printOutput(testOutputFile);
} catch (Exception e) {
e.printStackTrace();
fail();
} finally {
deleteSilent(testInputFile, testOutputFile);
}
}
#Test
public void testMp() {
Path testInputFile = null, testOutputFile = null;
try {
testInputFile = prepareInputFile();
DiskFileItem di = new DiskFileItem("file", "text/plain", false, testInputFile.getFileName().toString(),
(int) Files.size(testInputFile), testInputFile.getParent().toFile());
try (OutputStream out = di.getOutputStream();
InputStream in = Files.newInputStream(testInputFile)) {
IOUtils.copy(in, out);
}
CommonsMultipartFile cmf = new CommonsMultipartFile(di);
System.out.println("Size: " + cmf.getSize());
testOutputFile = testInputFile.getParent().resolve("testMpOutput.txt");
cmf.transferTo(testOutputFile.toFile());
printOutput(testOutputFile);
} catch (Exception e) {
e.printStackTrace();
fail();
} finally {
deleteSilent(testInputFile, testOutputFile);
}
}
private Path prepareInputFile() throws IOException {
Path tmpDir = Paths.get(System.getProperty("java.io.tmpdir"));
Path testInputFile = tmpDir.resolve("testMpinput.txt");
try (OutputStream out = Files.newOutputStream(testInputFile)){
out.write("Just a test.".getBytes(CS));
}
return testInputFile;
}
private void printOutput(Path p) throws IOException {
byte[] outBytes = Files.readAllBytes(p);
System.out.println("Output: " + new String(outBytes, CS));
}
private void deleteSilent(Path... paths) {
for (Path p : paths) {
try { if (p != null) p.toFile().delete(); } catch (Exception ignored) {}
}
}
}
The custom LocalFileItem class, YMMV!
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemHeaders;
public class LocalFileItem implements FileItem {
private static final long serialVersionUID = 2467880290855097332L;
private final Path localFile;
public LocalFileItem(Path localFile) {
this.localFile = localFile;
}
#Override
public void write(File file) throws Exception {
Files.move(localFile, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
}
#Override
public long getSize() {
// Spring's CommonsMultipartFile caches the file size and uses it to determine availability.
long size = -1L;
try {
size = Files.size(localFile);
} catch (IOException ignored) {}
return size;
}
#Override
public void delete() {
localFile.toFile().delete();
}
/* *** properties and unsupported methods *** */
private FileItemHeaders headers;
private String contentType;
private String fieldName;
private boolean formField;
#Override
public FileItemHeaders getHeaders() {
return headers;
}
#Override
public void setHeaders(FileItemHeaders headers) {
this.headers = headers;
}
#Override
public InputStream getInputStream() throws IOException {
throw new IOException("Only method write(File) is supported.");
}
public void setContentType(String contentType) {
this.contentType = contentType;
}
#Override
public String getContentType() {
return contentType;
}
#Override
public String getName() {
return localFile.getFileName().toString();
}
#Override
public boolean isInMemory() {
return false;
}
#Override
public byte[] get() {
throw new RuntimeException("Only method write(File) is supported.");
}
#Override
public String getString(String encoding)
throws UnsupportedEncodingException {
throw new RuntimeException("Only method write(File) is supported.");
}
#Override
public String getString() {
throw new RuntimeException("Only method write(File) is supported.");
}
#Override
public String getFieldName() {
return fieldName;
}
#Override
public void setFieldName(String name) {
this.fieldName = name;
}
#Override
public boolean isFormField() {
return formField;
}
#Override
public void setFormField(boolean state) {
this.formField = state;
}
#Override
public OutputStream getOutputStream() throws IOException {
throw new IOException("Only method write(File) is supported.");
}
}

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.

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