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You can set environment variables or pass them in using the -Dvariablename syntax

SET logfile=/location/to/my/log/file.log

or

java -Dlogfile=/location/to/my/log/file.log HelloWorld

When you want to access these environment variables from your Java source file you can use

Java 1.5 and newer:

String logfileLocation = System.getenv("logfile");

Java 1.4 and older:

String logfileLocation = System.getProperty("logfile");

I found this very useful web site that allows you to search what JAR file a specific Java class belongs to. This has proven quite useful to me over the last couple of days when I had to deal with NoClassDefFoundError and ClassNotFoundException problems.

You can just enter the name of the class or JAR file your looking for and the site will display the result.

http://www.findjar.com/index.jsp

I’ve used JMock for quite some time and I’ve found it to be a great and very useful mocking framework for unit testing. I was never quite happy with the syntax though; especially the part where you specify expectations.  Here’s a JMock snippet illustrating an expectation and a return value from a mocked object

context.checking(new Expectations() {{
    oneOf (department).employees(); will(returnIterator(employees));
}});

In Mockito the equivalent code would look like this

when(department.employees()).thenReturn(employees);

I find the Mockito syntax to be easier to write and understand. I’ve seen fellow developers implement JMock expectations in a way where they actually didn’t perform a useful test, and I think the sometimes confusing syntax of JMock was the reason. I’m not dismissing JMock as an inferior mocking framework, but I do think that the learning curve is a bit steeper. If you haven’t used Mockito yet I encourage you to take a look at it.

I noticed that I had almost no space left on my MacBook and I couldn’t see a good reason why I would have so little space left. In Windows I used an excellent application called WinDirStat to find out what was wasting space on my harddrive, and I was glad to see that there’s a similar app for OS X called Disk Inventory X. Both of these free and excellent applications  shows you a graphical tree map that makes it easy to see what is using up your disk space. In my case it turned out to be Entourage which due to frequent crashes had led to multiple copies of the Entourage database. I deleted several copies of the database and recovered a lot of space.

Disk Inventory X: http://www.derlien.com/

Location of Entourage files: http://www.entourage.mvps.org/path/index.html#ent_db

I spent some time looking this up and hopefully I will save someone else time on this. The current work directory for an application in Java is stored in the system property “user.dir”. This is the default directory that you application will write files to if you don’t specify an absolute file location. You can access it using this Java syntax:

String userDir = System.getProperty("user.dir");

I wanted to see the full Maven pom.xml structure and I found the following page on the Maven web site that contains all the elements and descriptions.

http://maven.apache.org/ref/2.2.0/maven-model/maven.html

I had a need to identify what process ID (PID) on my MacBook running OSX that had a specific IP address and port open so that I could kill it. It took me a while to figure this out but eventually I found something that worked.

lsof -i

This will show you

COMMAND     PID     USER        FD   TYPE  DEVICE     SIZE/OFF  NODE  NAME
Microsoft   280     someuser    15u  IPv4  0x8862e64       0t0  TCP   *:3546 (LISTEN)
...