ErrorLogger

ErrorLogger.java

/**
 * Custom logger to save errors.
 *
 * @author Icyene
 */

public class ErrorLogger extends PluginLogger {

    String PLUGIN_NAME = "NULL", TICKET_TRACKER = "NULL", PLUGIN_PACKAGE = "NULL", ENDL = "\n=====================================================";
    Plugin PLUGIN = null;

    public ErrorLogger(Plugin context) {
        super(context);
        this.PLUGIN = context;
    }

    public ErrorLogger(Plugin context, String name, String pack, String tracker) {
        super(context);
        this.PLUGIN_NAME = name;
        this.PLUGIN_PACKAGE = pack;
        this.TICKET_TRACKER = tracker;
        StringBuilder temp = new StringBuilder();
        for (int i = 0; i < name.length(); ++i)
           temp.append('=');
        this.ENDL = this.ENDL + temp.toString();
    }

    public void setName(String name) {
        this.PLUGIN_NAME = name;
    }

    public void setPackage(String pack) {
        this.PLUGIN_PACKAGE = pack;
    }

    public void setTracker(String tracker) {
        this.TICKET_TRACKER = tracker;
    }

    @Override
    public void log(LogRecord logRecord) {
           if(!generateErrorLog(logRecord))
               super.log(logRecord);
    }

    private boolean generateErrorLog(LogRecord record) {
        PluginDescriptionFile pdf = PLUGIN.getDescription();
        Server server = Bukkit.getServer();
        Throwable thrown;
        if((thrown=record.getThrown()) == null)
            return false;
        String error = ExceptionUtils.getStackTrace(thrown);
        if (!error.contains(PLUGIN_PACKAGE) && !error.contains(PLUGIN_NAME + " has encountered an error!") && !error.contains(this.getClass().getName()))  //Check if its not our own
            return false;
        StringBuilder err = new StringBuilder();
        boolean disable = false;
        err.append("\n=============" + PLUGIN_NAME + " has encountered an error!=============");
        err.append("\nStacktrace:\n" + error);
        err.append("\n" + PLUGIN_NAME + " version: " + pdf.getVersion());
        err.append("\nBukkit message: " + record.getMessage());
        err.append("\nPlugins loaded: " + Arrays.asList(server.getPluginManager().getPlugins()));
        err.append("\nCraftBukkit version: " + server.getBukkitVersion());
        err.append("\nJava version: " + getProperty("java.version"));
        err.append("\nOS info: " + getProperty("os.arch") + " " + getProperty("os.name") + ", " + getProperty("os.version"));
        err.append("\nPlease report this error to the " + PLUGIN_NAME + " ticket tracker (" + TICKET_TRACKER + ")!");
        error = error.toLowerCase();
        if (error.contains("nullpointerexception") || error.contains("stackoverflowexception")) {
            err.append("\nA critical error has been thrown. " + PLUGIN_NAME + " has been disabled to prevent further damage.");
            disable = true;
        } else {
            err.append("\nError was minor; " + PLUGIN_NAME + " will continue operating.");
        }
        String name = PLUGIN_NAME + "_" + md5(err).substring(0, 6) + ".error.log"; //Name is PLUGIN_NAME with first 6 chars of md5 appended
        File root = new File(PLUGIN.getDataFolder(), "errors");
        if (!root.exists())
            root.mkdir();
        File dump = new File(root.getAbsoluteFile(), name);

        if (!dump.exists()) {
            try {
                dump.createNewFile();
                BufferedWriter writer = new BufferedWriter(new FileWriter(dump));
                writer.write((err.toString() + ENDL).substring(1)); //Remove the extra /n
                writer.close();
                err.append("\nThis has been saved to the file ./" + PLUGIN.getName() + "/errors/" + name);
            } catch (Exception e) {
                System.err.println("Ehm, errors occured while displaying an error >.< Stacktrace:\n");
                e.printStackTrace();
            }
        }
        err.append(ENDL);
        System.err.println(err);

        if (disable)
            Bukkit.getServer().getPluginManager().disablePlugin(PLUGIN);
        return true;
    }

    public void initErrorHandler() {
        Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
            @Override
            public void uncaughtException(Thread thread, Throwable throwable) {
                LogRecord o_u_screwd = new LogRecord(Level.SEVERE, "Uhoh");
                o_u_screwd.setThrown(throwable);
                generateErrorLog(o_u_screwd);
            }
        });
    }

    private String md5(StringBuilder builder) {
        String hash = "";
        try {
            MessageDigest m = MessageDigest.getInstance("MD5");
            m.reset();
            m.update(builder.toString().getBytes());
            hash = new BigInteger(1, m.digest()).toString(16);
            while (hash.length() < 32) {
                hash = 0 + hash;
            }
        } catch (NoSuchAlgorithmException e) {
        }
        return hash;
    }
}

Updated to use ExceptionUtils from Apache instead of my own getStackTrace.

Has variable number of '=' to ENDL!