Java Platform

Java 5 New Features	http://java.sun.com/developer/technicalArticles/releases/j2se15/
Java 6 New Features	http://java.sun.com/developer/technicalArticles/J2SE/Desktop/javase6/beta2.html

Coverage Tools

Emma	http://emma.sourceforge.net
Emma Eclipse Plugin	http://www.eclemma.org

Integrated Development Environments

Eclipse	http://www.eclipse.org
IntelliJ IDEA	http://www.jetbrains.com/idea
NetBeans	http://www.netbeans.org
Together Architect	http://www.borland.com/us/products/together/index.html

News Sites

InfoQ	http://www.infoq.com
Java.net	http://java.net
The Register	http://www.theregister.co.uk
ZDNet	http://news.zdnet.com

Static Analysis Tools

Static analysis tools that are available stand-alone or as an addition to an IDE.

Checkstyle	http://checkstyle.sourceforge.net
Eclipse Test and Performance Tools Platform	http://www.eclipse.org/tptp
Findbugs	http://findbugs.sourceforge.net
PMD	http://pmd.sourceforge.net

UML Modelling

UML modelling packages. See also IDEs to see which also support java development.

Enterprise Architect	http://www.sparxsystems.com.au/products/ea/index.html
Together Architect	http://www.borland.com/us/products/together/index.html
Rational Rose	http://www.ibm.com/software/rational

Unit Testing

Unit and component testing support components.

JUnit	http://www.junit.org
TestNG	http://testng.org
EasyMock	http://www.easymock.org