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.

daysBeteenDates will calculate the number of days between 2 dates in the form of 'YYYY-MM-DD'.

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");

This function will take four arguments, the year, month, day and number of days in the future you want to go and return to you as an array (year,month,day) of that date.

It is a simple function that is only for convenience. It is meant to be used in conjunction with the list() command.

This function will let you find the Sunday, Monday, Tuesday, etc of a month and return to you that date.

It is a modification of a script I found online at this site: http://filchiprogrammer.wordpress.com/2008/02/27/getting-the-first-monday-of-the-month/.

The function takes three arguments, the month, year and the weekday you are looking for. The weekday is represented by an integer, 0 for Sunday, 1 for Monday and so on.