Java Utililty Methods Unzip File

Set<String> added = new HashSet<String>();
ZipInputStream inStream = null;
try {
    inStream = new ZipInputStream(new FileInputStream(zippedFile));
    ZipEntry entry;
    byte[] buffer = new byte[1024];
    while ((entry = inStream.getNextEntry()) != null) {
        String name = entry.getName();
...

targetDir.mkdirs();
ZipFile zipFile = new ZipFile(zippedFile);
try {
    Enumeration<? extends ZipEntry> entries = zipFile.entries();
    while (entries.hasMoreElements()) {
        ZipEntry entry = entries.nextElement();
        File targetFile = new File(targetDir, entry.getName());
        if (entry.isDirectory()) {
...

final ZipInputStream zis = new ZipInputStream(new ByteArrayInputStream(zippedContent));
final Map<String, byte[]> resources = new HashMap<String, byte[]>();
try {
    ZipEntry entry = zis.getNextEntry();
    while (entry != null) {
        final ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            int len;
...

ZipEntry entry;
while ((entry = from.getNextEntry()) != null) {
    if (entry.isDirectory()) {
        new File(dir, entry.getName()).mkdirs();
    } else {
        final File file = new File(dir, entry.getName());
        file.getParentFile().mkdirs();
        file.createNewFile();
...

if (!zip.exists())
    throw new FileNotFoundException("Cannot find " + zip);
if (!dir.exists())
    throw new FileNotFoundException("Cannot find " + dir);
if (!zip.isFile())
    throw new FileNotFoundException("Zip file must be a file " + zip);
if (!dir.isDirectory())
    throw new FileNotFoundException("Dir argument must be a directory " + dir);
...

final String destDirAbsPath = destDir.getAbsolutePath() + File.separatorChar;
final byte[] buf = new byte[2048];
ZipInputStream ziStream = null;
FileInputStream fiStream = null;
try {
    fiStream = new FileInputStream(zipFile);
    ziStream = new ZipInputStream(fiStream);
    ZipEntry zipEntry = ziStream.getNextEntry();
...

boolean MAC_OS_X = System.getProperty("os.name").toLowerCase().startsWith("mac os x");
int buf_size = 2048;
try {
    BufferedOutputStream dest; 
    FileInputStream fis = new FileInputStream(zipFile);
    ZipInputStream zis = new ZipInputStream(new BufferedInputStream(fis));
    ZipEntry entry;
    while ((entry = zis.getNextEntry()) != null) {
...

if (is == null) {
    throw new IOException("The inputStream is null");
if (outputDirectory == null) {
    throw new IOException("The output directory is null");
if (!(outputDirectory.exists() && outputDirectory.isDirectory())) {
    throw new IOException("The output directory is invalid (" + outputDirectory + ")");
...

if (targetFolder.exists()) {
    if (!targetFolder.isDirectory()) {
        throw new IllegalArgumentException(
                String.format("Given existing target folder '%1$s' is not a directory!", targetFolder));
} else {
    if (!targetFolder.mkdirs()) {
        throw new IOException(String.format("Could not create target folder '%1$s'!", targetFolder));
...

ByteArrayOutputStream fout = null;
try {
    final ByteArrayInputStream in = new ByteArrayInputStream(result.getBytes("ISO-8859-1"));
    final ZipInputStream zin = new ZipInputStream(in);
    while ((zin.getNextEntry()) != null) {
        fout = new ByteArrayOutputStream();
        for (int c = zin.read(); c != -1; c = zin.read()) {
            fout.write(c);
...