"2SE provides the essential compiler, tools, runtimes, and APIs for
writing, deploying, and running applets and applications in the Java
programming language." -- java.sun.com

What that means from the little i have used J2SE is that it provides a
means of deploying java software. It contains a few more library
functions and media runtimes.

Here is a list, of the extra libraries. I personally dont call it
technology as its not a different technology, its just extensions:

J2SE Component Links

Assistive Technologies
Drag and Drop
Java Access Bridge
JavaBeans Technology
JavaBeans Activation Framework JAF 1.0.2
Javadoc Tool
Java Foundation Classes (JFC)/Swing
Java HotSpot Virtual Machine
Java Platform Debugger Architecture (JPDA)
Java Plug-in for Windows XP
Java 2D API product page
Java Web Start
JDBCTM Technology
Pluggable Look and Feel
Remote Method Invocation (RMI)
Security

J2SE Optional Packages (formerly Standard Extensions)

InfoBus
Java Advanced Imaging
Java Authentication and Authorization Service (JAAS)
Java Communications API (JCA)
Java Cryptography Extension (JCE)
Java Data Objects (JDO)
Java Help Technology
Java Management Extensions (JMX)
Java Media APIs
Java Media Framework (JMF)
Java Naming and Directory Interface (JNDI)
Java Secure Socket Extension (JSSE)
Java Speech API
Java 3D API