Java Archive

This article explains how to develop and implement trees in the Standard Widget Toolkit. Learn how an SWT tree is created and populated with data, how columns can be used to categorize data, how a tree can be extended to support row sorting, and how the tree's content can be searched.

An understanding of native memory is essential when you design and run large Java applications. The lack of predictable behaviour means there's no one simple way to identify native-memory exhaustion. Instead, you need to use data from the OS and from the Java runtime to confirm the diagnosis. To get the best performance from your Java application, you must understand how the application affects the Java runtime's native-memory use.

Version 5 of the Java Language Specification added 10 new methods to java.lang.Math and java.lang.StrictMath, and Java 6 added another 10. Join Elliotte Rusty Harold for a look into "new" features in the classic java.lang.Math class in this article, which explores the functions designed for operating on floating-point numbers.

Robert Schuster has a very detailed account of the work done to get full Java support on small devices. He managed to cross compile (and package) OpenJDK/IcedTea for OpenEmbedded/ARM through multiple build stages using various free java implementations. This provides full free (GPL) J2SE support for ARM based handlhelds, phones and embedded devices like the BeagleBoard, BUG, OpenMoko, Maemo and the Irex Iliad through Jalimo.

Guice is Google's open source dependency injection framework for Java development. It enables better testing and modularity by taking away the pain of writing your own factories. This article offers a tour of the most important Guice concepts that will leave you ready to Guice up your applications.

Sun has released the first version of JavaFX, aptly named JavaFX 1.0. "JavaFX 1.0 returns to the sales pitch that Sun used during Java's launch more than 13 years ago: a foundation for software on a wide variety of computing "clients" such as desktop computers or mobile phones. JavaFX builds on current Java technology but adds two major pieces. First is a new software foundation designed to run so-called rich Internet applications--network-enabled programs with lush user interfaces. Second is a new programming language called JavaFX Script that's intended to be easier to use than traditional Java."

Today was one of those days when I wished Java would support multiple return values. I had to develop a rather CPU-intensive algorithm which would compute a solution for a knotty constraint problem. Having a solution alone is sometimes not enough and you also need to add some parameters which measure the quality of the computed outcome. Most of these accompanying parameters can or have to be computed within the algorithm itself, but Java allows you to return only one value either an object or a primitive type. People working with Lisp, MATLAB or Perl, just to mention a few, don't have a problem like this at all. Functions supporting multiple return values is already implemented at the language level and frameworks make heavy use of this. But as a Java programmer you are pretty much stuck here and need to consider some other means to come out of this situation. In the following I would like to give some hints on that topic. Hopefully they are of help for anyone having the same problem every now and then.

Wildcards can be very confusing when it comes to generics in the Java language, and one of the most common mistakes is to fail to use one of the two forms of bounded wildcards ("? super T" and "? extends T") when needed. You've made this mistake? Don't feel bad, even the experts have, and this month Brian Goetz shows you how to avoid it.

Back in May 2006, Sun announced during the JavaOne conference it would release Java as open source, licensed as GPL software. While it was released as GPL, it still contained about 5 percent proprietary, non-free code - the Java trap, as the FSF calls it. The FSF called to dismantle this trap, and now the IcedTea project has reached an important milestone.

JNode 0.2.6 has been released. "JNode is a free, open source Java technology based OS written fully in Java language (with a very small assembler nano-kernel). This release features over 99 percent java 6 api compatibility, hotswapping, nfs, hfs+, even more openJDK integration, jetty6 and of course bug fixes and improvements."

The IcedTea project added a PowerPC Java port (both 32 and 64 bit) of OpenJDK. IcedTea 1.5 now also tracks the mercurial repo, provides better GNU/Linux integration by using standard system libraries (libpng, libjpeg, zlib, giflib) and can be bootstrapped with the free gcj/ecj/classpath toolchain. OpenJDK just accepted a new porters group and Gary Benson wrote a guide to porting IcedTea that might be the start of a lot of other Java ports.

Straight from the ADC site (a free online account is enough to gain access to the download): "Java SE 6 Developer Preview 8 is an implementation of Sun's Java SE 6 for Mac OS X v10.5.1 and later. This Preview includes Java SE 6 version 1.6.0_01. This Developer Preview does not change the default version of Java. This release is only for Mac OS X v10.5.1 and later, and should not be installed on earlier versions of Mac OS X. This release is for 64-bit Intel-based Macs only and cannot run on PowerPC-based or 32-bit Intel-based Macs."

GNU Classpath 0.96 "Staying Alive!" and IcedTea 1.4 just got released. GNU Classpath is slowly turning into a bootstrapping platform for IcedTea/OpenJDK by providing the necessary free software plugs that are missing from Sun's OpenJDK to provide various GNU/Linux distributions with the fully free GPLed IcedTea Java platform implementation that will be in the Fedora (Werewolf), Debian, and Ubuntu (Gutsy) releases.

Java Platform, Standard Edition 6 focuses on performance, with expanded tools for managing and monitoring applications as well as diagnosing common problems. This article outlines the basis of monitoring and management in the Java SE platform and provides detailed information about the relevant enhancements in Java SE 6.