Most Java programmers know to use a StringBuffer (or a JDK 1.5 StringBuilder) when concatenating Strings in Java, but it occurred to me that the compiler might be able to optimize some of these calls. For instance, look at the following code: StringBuffer buf = new StringBuffer(); buf.append(“one” + “two”); There is an obvious optimization … Continue reading On Java String Concatenation
I picked up a nice little tip for easy conversion between an int and a String. Previously I'd always done something like int one = 1; String str = String.valueOf(one); The alternative is int one = 1; String str = one + “”; From the bytecode point of view it isn't quite as efficient: L0 … Continue reading Cute way to convert an int to a String
HTML 5 includes the <video> tag to enable embedding of video. Unfortunately, and unlike Flash, there is no way to directly use a webcam with it. However, if you want to experiment with it some VLC+Apache magic can help. Firstly, you need to setup VLC to do HTTP streaming. These instructions are for windows, but … Continue reading Using a webcam with HTML 5
I’ve been doing random MP3 metadata work lately. Here’s some code which others might find useful. Extracting MP3 tags from mp3 file hosted on server using HTTP Range queries. So I was using Apache Tika for various metadata stuff. I wanted to get the song title for a file hosted on a server, but Tika … Continue reading Random MP3 metadata code
Linking to native code in Java is always a hassle. JNI isn’t exactly nice, and there are some oddities around classloaders and native libraries which are annoying if you run into them. One thing I wasn’t aware of was exactly how hard it is to load a library it isn’t already in the directories specified … Continue reading Modify java.library.path at runtime
Getting this error in Tomcat? java.lang.NoSuchMethodError: org.w3c.dom.Node.getTextContent()Ljava/lang/String; There’s a good chance you installed Tomcat with the JDK 1.4 Compatibility package and are now running under JDK 5. To fix it, delete xercesImpl.jar, xml-apis.jar and xalan.jar from $CATALINA_HOME\common\endorsed\
I've switched my feeds at my BadMagicNumber blog to be published via FeedBurner. There should be no disruption to your normal programming, although I think some aggregators will show some non-new items as new. I switched the feeds over using a simple Servlet Filter. If anyone wants to do the same, here's the code. This … Continue reading Switched to Feedburner
Modern CPUs have many features that increase multi-threaded performance (eg: hyperthreading on Pentium 4s and similar features on recent PowerPC chips). Over the next year the trend towards multi-cored CPUs from AMD, Intel and Sun will accelerate multithreaded performance while single threaded performance will begin to level off. Java has always had excellent threading support, … Continue reading Using JDK 1.5 to optimize for modern CPUs
Tim Bray's post on Technorati Tags highlighted that it wasn't just me that though disambiguation in folksonomies is important. I spent a while thinking about it, and I came up with a half-backed scheme where uses could qualify their tags with a parent tag, and an elaborate justification for why this was okay to do. … Continue reading Disambiguation in Folksonomies
If you are creating a publically available webservice, make sure it is available over HTTPS and encourage people to use the HTTPS version. There are way too many badly behaved firewalls and proxies (from companies that should know better) that munge things in ways that are very hard to debug. For instance (just as a … Continue reading All Web Services should be run over HTTPS