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    public static byte[] intToByteArray(int value) {
        byte[] b = new byte[4];
        for (int i = 0; i < 4; i++) {
            int offset = (b.length - 1 - i) * 8;
            b[i] = (byte) ((value >>> offset) & 0xFF);
        }
        return b;
    }
                
                    Useful class for converting Image objects into BufferedImage objects.  This is necessary if you are doing image manipulation since the majority of image manipulation code in Java processes BufferedImage objects.

import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;

/**
 * @author Anthony Eden
 */
public class BufferedImageBuilder {

    private static final int DEFAULT_IMAGE_TYPE = BufferedImage.TYPE_INT_RGB;

    public BufferedImage bufferImage(Image image) {
        return bufferImage(image, DEFAULT_IMAGE_TYPE);
    }

    public BufferedImage bufferImage(Image image, int type) {
        BufferedImage bufferedImage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        Graphics2D g = bufferedImage.createGraphics();
        g.drawImage(image, null, null);
        waitForImage(bufferedImage);
        return bufferedImage;
    }

    private void waitForImage(BufferedImage bufferedImage) {
        final ImageLoadStatus imageLoadStatus = new ImageLoadStatus();
        bufferedImage.getHeight(new ImageObserver() {
            public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {
                if (infoflags == ALLBITS) {
                    imageLoadStatus.heightDone = true;
                    return true;
                }
                return false;
            }
        });
        bufferedImage.getWidth(new ImageObserver() {
            public boolean imageUpdate(Image img, int infoflags, int x, int y, int width, int height) {
                if (infoflags == ALLBITS) {
                    imageLoadStatus.widthDone = true;
                    return true;
                }
                return false;
            }
        });
        while (!imageLoadStatus.widthDone && !imageLoadStatus.heightDone) {
            try {
                Thread.sleep(300);
            } catch (InterruptedException e) {

            }
        }
    }

    class ImageLoadStatus {

        public boolean widthDone = false;
        public boolean heightDone = false;
    }

}
                
                    Join a collection of objects into a String using the specified delimiter.  One thing to note is that the collection can contain any object.  The object's toString() method will be used to convert said object to its String representation.

    public static String join(Collection s, String delimiter) {
        StringBuffer buffer = new StringBuffer();
        Iterator iter = s.iterator();
        while (iter.hasNext()) {
            buffer.append(iter.next());
            if (iter.hasNext()) {
                buffer.append(delimiter);
            }
        }
        return buffer.toString();
    }
                
                    This class is useful for printing the data coming through an InputStream without copying that data into memory first.

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

public class DebugInputStream extends FilterInputStream {

    private OutputStream debugOut;

    public DebugInputStream(InputStream in, OutputStream debugOut) {
        super(in);
        this.debugOut = debugOut;
    }

    public int read() throws IOException {
        int c = super.read();
        debugOut.write((char) c);
        return c;
    }

    public int read(byte[] b) throws IOException {
        int readCount = super.read(b);
        for (int i = 0; i < readCount; i++) {
            debugOut.write((char) b[i]);
        }
        return readCount;
    }

    public int read(byte[] b, int offset, int length) throws IOException {
        int readCount = super.read(b, offset, length);
        int readTo = offset + readCount;
        for (int i = offset; i < readTo; i++) {
            debugOut.write((char) b[i]);
        }
        return readCount;
    }

}
                
                    From: <a href="http://talideon.com/weblog/2005/02/detecting-broken-images-js.cfm">http://talideon.com/weblog/2005/02/detecting-broken-images-js.cfm</a>.

Called in an onload listener to see if an image object has managed to load properly.
function isImageOk(img) {
    // During the onload event, IE correctly identifies any images
    // that weren't downloaded as not complete. Others should too.
    // Gecko-based browsers act like NS4 in that they report this
    // incorrectly: they always return true.
    if (!img.complete) {
        return false;
    }

    // However, they do have two very useful properties: naturalWidth
    // and naturalHeight. These give the true size of the image. If
    // it failed to load, either of these should be zero.
    if (typeof img.naturalWidth != "undefined" && img.naturalWidth == 0) {
        return false;
    }

    // No other way of checking: assume it's ok.
    return true;
}
Works fine in IE and Gecko. Not tested (as yet) in Opera or Safari.                
                    Sometimes while I'm editing, I want to convert a region to HTML. I use Perl's HTML::FromText. First I create this script and call it <em>tohtml</em>.

#!/usr/bin/perl

 use HTML::FromText;
 use strict;

 my $text = join '',<>;
 my $html = text2html($text, urls => 1, email => 1, bold=>1, paras => 1, allcaps => 1, tables => 1, bullets => 1, underline=>1);

print $html;

Then from within Emacs, I select the region and do

C-x ESC-1 ESC-| tohtml RET
                
                    use with caution!  This script will copy your pub key to a remote host so you can login or run remote scripts without a password.  IMPORTANT: if you need to run a single script on the remote host, it would be better to authorize a key for just that script.

#!/bin/bash
# kumar.mcmillan -at- farmdev.com

function usage()
{
    echo ""
    echo "Authorizes a host for automatic SSH use by sending your key to the remote host ..."
    echo "Usage: $0 remote_host_to_authorize [username:=defaults to current username]"
    echo ""
}

function cleanup()
{
    if [ -f $TEMP_PUB_KEY_XFER ]
    then
        rm $TEMP_PUB_KEY_XFER
    fi
}

function exit_on_error()
{
    cleanup
    exit 1
}

if [ $# -lt 1 -o "$1" = "-h" -o "$1" = "--help" ]
then
    usage
    exit 0
fi

PUB_KEY=~/.ssh/id_dsa.pub
if [ $# -eq 2 ]; then
    USER=$2
else
    USER=`whoami`
fi
HOST_TO_AUTH=$1
TEMP_PUB_KEY_XFER=/tmp/$USER"_TEMP_KEY"

echo "checking for $PUB_KEY ..."
if [ ! -f $PUB_KEY ]; then
    echo "generating your dsa public key (leave passphrase blank and save to $PUB_KEY when prompted) ..."
    ssh-keygen -t dsa
    if [ $? -ne 0 ]; then
        echo "ssh-keygen failed"
        exit_on_error
    fi
fi
echo "OK"

echo "for the following commands you will be asked to supply your password for $HOST_TO_AUTH :"

echo "copying a temp pub key to $HOST_TO_AUTH ..."
cat $PUB_KEY > $TEMP_PUB_KEY_XFER
chmod 700 $TEMP_PUB_KEY_XFER
echo "OK"

remote_key=`basename $TEMP_PUB_KEY_XFER`
scp $TEMP_PUB_KEY_XFER $USER@$HOST_TO_AUTH:~/$remote_key
if [ $? -ne 0 ]; then
    echo "scp failed"
    exit_on_error
fi
    
echo "authorizing $HOST_TO_AUTH for automatic SSH use ..."
ssh $USER@$HOST_TO_AUTH "cat ~/$remote_key >> ~/.ssh/authorized_keys; rm ~/$remote_key"
if [ $? -ne 0 ]; then
    echo "ssh failed"
    exit_on_error
fi
echo "OK"

cleanup
echo "authorization successful!  you can now login automatically to $HOST_TO_AUTH"
exit 0
                
                    
Object[] array = new Object[]{"12","23","34"};
java.util.List list = Arrays.asList(array);
                
                    If you use vi to edit files, it leaves your backup copies with tildes at the end.  Adding this to your .htaccess file (or virtual host directive in your apache conf) stops people being able to access them.

(Requires mod_rewrite)

RewriteEngine on
RewriteRule  ~$   - [F]

                
                    
require 'digest/sha1'
sha1 = Digest::SHA1.hexdigest('something secret')