monline

"Thread Weaver is a framework for writing multi-threaded unit tests in Java. It provides mechanisms for creating breakpoints within your code, and for halting execution of a thread when a breakpoint is reached. Other threads can then run while the first thread is blocked. This allows you to write repeatable tests for that can check for race conditions and thread safety."

"tcpmon is an open-source utility for monitoring the data flowing on a TCP connection. tcpmon is used by placing it in-between a client and a server. The client is made to connect to tcpmon, and tcpmon forwards the data to server along-with displaying it in its GUI."

Theoretically the above link takes you to the most recent version of tcpmon. However the project started as an Apache tool. At tcpmon.dev.java.net you can get v1.1 and at ws.apache.org v1.0. But the two are not identical featurewise! The new version lacks the ability to switch between horizontal and vertical layout and more importantly it lacks the XML rendering mode. The latter displays XML content structured, ie. the various nodes are indented based on their level in the XML tree. Unfortunately the old version uses some fixed size font which gets pretty much unreadable at higher resolutions.

It took me a few minutes to find so it might be useful for others if I share. There are indeed pre-packaged source bundles for every Eclipse release available and theoretically you should be able to compile your own eclipse build fairly easily.

The method of discovering a suitable XML Parser is pretty well described in the javadoc of the newInstance function of the javax.xml.parsers.DocumentBuilderFactory class.

It's not a big deal, really. However the MAC address is only available since Java6 and to create a Java5 compatible class for working with network interfaces, you've to use the Java reflection API. My demo class might be of help to those who have not yet used reflection. See the attachment for the source of my ListNetworkInterfaces class which will print MAC and IP addresses of all available network interfaces. It'll print MAC addresses only if invoked in a JRE6 (or later). Compilation and invocation is as usually:

There're a lot of ways to do this right and a lot of ways to do it wrong. Here's one method that I've found to be both correct (ie. for all possible integer values the following is true: value == byteArrayToInt(intToByteArray(value))) and efficient.

While creating a Java web application you'll most probably use various libraries pre-packaged into JAR files. And of course you'll create several JARs for your own code as well. However some of these JARs might share the same classes and most of the time there's no guarantee on from which JAR a class is loaded. Your best bet is to make sure that each class (that you need) is present only in one JAR in you lib folder. To find classes that occur more than once in a webapp library folder, I've written a short shellscript.

I've found Angelica's page (the "Under The Hood Of The Compiler" section in her Java Generics FAQ) by googling for possible workarounds/solutions for the various "unchecked" warnings we get in all sorts of Java code.

I'm very impressed. Both with the clarity and quaility of her website (there's quite some work in it), the FAQ she published on it and her career as well. She resembles quite a lot of what I'd like to achieve in my professional life.

I was not completely sure about the order that try-catch-finally blocks are executed in (eg. if an exception occurs in a catch block, then is the immediatly following finally block executed next or the catch block that catches the exception?), so I made a small test case that demostrates workflow (order of execution) of the various blocks.

Tomcat's class loading can be tricky some times. If you search on class loading problems, you'll find myriads of posts on blogs, forums, etc. And it's not just because people don't know how it works (which is actually well documented), but because it sometimes doesn't work. There've been bugs in Tomcat's class loading and even if it's working as expected, it can give you a hard time to track down what's actually happening behind the scene.