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Thread: Java Issue / Cache issue

  1. #1
    Junior Member
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    Default Java Issue / Cache issue

    What I'm trying to do it load the cache on a web client, this is the error:



    Java Plug-in 1.6.0_31
    Using JRE version 1.6.0_31-b05 Java HotSpot(TM) Client VM
    User home directory = C:\Users\Jerry and Christine
    ----------------------------------------------------
    c: clear console window
    f: finalize objects on finalization queue
    g: garbage collect
    h: display this help message
    l: dump classloader list
    m: print memory usage
    o: trigger logging
    q: hide console
    r: reload policy configuration
    s: dump system and deployment properties
    t: dump thread list
    v: dump thread stack
    x: clear classloader cache
    0-5: set trace level to <n>
    ----------------------------------------------------


    java.lang.UnsupportedClassVersionError: client : Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknow n Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknow n Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Un known Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.defineClassH elper(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.access$100(U nknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader$2.run(Unknow n Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.plugin2.applet.Plugin2ClassLoader.findClassHel per(Unknown Source)
    at sun.plugin2.applet.Applet2ClassLoader.findClass(Un known Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass0(U nknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadClass(Un known Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.plugin2.applet.Plugin2ClassLoader.loadCode(Unk nown Source)
    at sun.plugin2.applet.Plugin2Manager.createApplet(Unk nown Source)
    at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
    Exception: java.lang.UnsupportedClassVersionError: client : Unsupported major.minor version 51.0


    And here is the code:

    import java.io.File;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.io.FileWriter;
    import java.io.BufferedWriter;
    import java.io.BufferedOutputStream;
    import java.io.BufferedInputStream;
    import java.io.FileOutputStream;
    import java.io.FileInputStream;
    import java.io.InputStream;
    import java.net.URLConnection;
    import java.net.URL;
    import java.util.zip.ZipFile;
    import java.util.zip.ZipEntry;
    import java.util.zip.ZipInputStream;
    import java.util.Enumeration;

    import sign.signlink;

    public class CacheDownloader {

    private client client;

    private final int BUFFER = 1024;

    private final int VERSION = 11; // Version of cache
    private String cacheLink = "http://dl.dropbox.com/u/51164319/cache.zip"; // Link to cache

    private String fileToExtract = getCacheDir() + getArchivedName();

    public CacheDownloader(client client) {
    this.client = client;
    }

    private void drawLoadingText(String text) {
    client.drawLoadingText(35, text);
    //System.out.println(text);
    }


    private void drawLoadingText(int amount, String text) {
    client.drawLoadingText(amount, text);
    //System.out.println(text);
    }

    private String getCacheDir() {
    return signlink.findcachedir();
    }

    private String getCacheLink() {
    return cacheLink;
    }

    private int getCacheVersion() {
    return VERSION;
    }

    public CacheDownloader downloadCache() {
    try {
    File location = new File(getCacheDir());
    File version = new File(getCacheDir() + "/cacheVersion" + getCacheVersion() + ".dat");

    if(!location.exists()) {
    //drawLoadingText("Loading new Updates....");
    downloadFile(getCacheLink(), getArchivedName());

    unZip();
    //System.out.println("UNZIP");

    BufferedWriter versionFile = new BufferedWriter(new FileWriter(getCacheDir() + "/cacheVersion" + getCacheVersion() + ".dat"));
    versionFile.close();
    } else {
    if(!version.exists()) {
    //drawLoadingText("Downloading Cache Please wait...");
    downloadFile(getCacheLink(), getArchivedName());

    unZip();
    //System.out.println("UNZIP");

    BufferedWriter versionFile = new BufferedWriter(new FileWriter(getCacheDir() + "/cacheVersion" + getCacheVersion() + ".dat"));
    versionFile.close();

    } else {
    return null;
    }
    }
    } catch(Exception e) {

    }
    return null;
    }

    private void downloadFile(String adress, String localFileName) {
    OutputStream out = null;
    URLConnection conn;
    InputStream in = null;

    try {

    URL url = new URL(adress);
    out = new BufferedOutputStream(
    new FileOutputStream(getCacheDir() + "/" +localFileName));

    conn = url.openConnection();
    in = conn.getInputStream();

    byte[] data = new byte[BUFFER];

    int numRead;
    long numWritten = 0;
    int length = conn.getContentLength();


    while((numRead = in.read(data)) != -1) {
    out.write(data, 0, numRead);
    numWritten += numRead;

    int percentage = (int)(((double)numWritten / (double)length) * 100D);
    drawLoadingText(percentage, "Downloading Cache " + percentage + "%");

    }

    System.out.println(localFileName + "\t" + numWritten);
    drawLoadingText("Finished downloading "+getArchivedName()+"!");

    } catch (Exception exception) {
    exception.printStackTrace();
    } finally {
    try {
    if (in != null) {
    in.close();
    }
    if (out != null) {
    out.close();
    }
    } catch (IOException ioe) {
    }
    }

    }

    private String getArchivedName() {
    int lastSlashIndex = getCacheLink().lastIndexOf('/');
    if (lastSlashIndex >= 0
    && lastSlashIndex < getCacheLink().length() -1) {
    return getCacheLink().substring(lastSlashIndex + 1);
    } else {
    //System.err.println("error retreiving archivaed name.");
    }
    return "";
    }




    private void unZip() {

    try {
    InputStream in =
    new BufferedInputStream(new FileInputStream(fileToExtract));
    ZipInputStream zin = new ZipInputStream(in);
    ZipEntry e;

    while((e=zin.getNextEntry()) != null) {

    if(e.isDirectory()) {
    (new File(getCacheDir() + e.getName())).mkdir();
    } else {

    if (e.getName().equals(fileToExtract)) {
    unzip(zin, fileToExtract);
    break;
    }
    unzip(zin, getCacheDir() + e.getName());
    }
    //System.out.println("unzipping2 " + e.getName());
    }
    zin.close();

    } catch(Exception e) {
    e.printStackTrace();
    }
    }

    private void unzip(ZipInputStream zin, String s)
    throws IOException {

    FileOutputStream out = new FileOutputStream(s);
    //System.out.println("unzipping " + s);
    byte [] b = new byte[BUFFER];
    int len = 0;

    while ((len = zin.read(b)) != -1) {
    out.write(b,0,len);
    }
    out.close();
    }
    }


  2. #2
    Super Moderator pbrockway2's Avatar
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    Default Re: Java Issue / Cache issue

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