Here's a nifty trick I often use for testing.

Lets say you have a c:\foo\lib directory full of jarfiles for log4j, javamail...whatever.

Modern J2EE containers do a nice job of letting you deploy a jarfile with your code and have a lib directory full of jarfiles like this, but what if you just want to run a quick client from the command line?

Here's what you do:

Another solution recommends using a text match pattern.
This works, but as long as you've got mail.jar in your classpath anyway, you might as well use this technique instead. (Plus, I think it works with older JDK 1.2+, whereas pattern.compile is 1.4+)

Note that it also accepts a comma-separated list of emails, just like a To: or CC: address line would.

I was looking for an easy way to populate a combo box with strings taken from an enumeration, and also to be able to pull out Enum objects from the combo box. After some searching, I found EnumComboBoxModel on the JDesktop website, but was not able to find any code.

Instead I came up with an easier solution that did not require me to define a new Model class, but instead uses javax.swing.DefaultComboBoxModel.

Sorry for the disorganization of the code, but hopefully you get the idea.

From time to time you may have reasons to override the default find method that ActiveRecord provides. In this example, we'll store a side-copy of the record attributes so that we have some basis for discovering changes to the data.

note: this will not override dynamic finders such as find_by_id

When doing a lot of testing in script/console, you often have to reload to pickup changes in DB schema, models and libs. The process of quitting the console and restarting it can become incredibly tedious amidst bugtracking.

note: I don't believe this reloads items in the libs dir

I'm in the process of writing test fixtures for our rails site. A lot of my tests require authentication, so I've had to port our permissions system into a fixture. Rather than type out all of the information for the fixture, I decided to create a nested loop that will take care of this for me.

There's probably a rake task for this, but I wasn't able to find it, so I came up with my own solution. You'll have to do a little cleanup when it's done, however some slight mods to this loop could even eliminate that.

Java properties files can yield undesirable results at runtime, if there happen to be spaces at the end of some lines.

Requires a win32 port for the GNU utilities grep and sed - e.g. http://unxutils.sourceforge.net/.

if you use the same buildfiles on your local codebase and your continuous integration buildserver, the if-attribute for ant's targets comes in handy...

for this ant buildfile snippet to only create+publish javadoc when executed on the buildserver, the buildserver only has to set the referred system property, e.g. on its startup by using a Java D-option "-Dcontinuous.build=true" ...

ant buildtool website

With Java Web Start 1.5.0 all of a sudden new proxy properties were introduced (deployment.proxy.http.host, deployment.proxy.http.port and deployment.proxy.bypass.list) valid only for the webstart environment - and if that was not enough yet, it does not support the existing proxy properties, neither the standard, nor the deprecated ones from old Java releases. To topple even that, for the bypass-list the delimiters were changed to semicolon (http.nonProxyHosts has the pipe char as delimiter) ...

standard networking properties

the workaround here makes sure, that if any one of these proxy properties (deprecated, standard or webstart-5 ones) are set, that all the others get the same settings - this pays off, if you're using different third-party components relying on one specific set of these proxy properties (especially if it's beyond your power, in what kind of environment the software will be executed respectively integrated...)

This is a quick and easy class that will generate MD5 hashes from strings. I originally wrote it to insert into my Oracle database so I could generate MD5 hases for passwords from PL/SQL.

Example

String md5Hash = stringMD5("my password");