Java 2 Micro Edition Overview - Java 2 Micro Edition Application Development - page 3

NullPointerException , Object , Runnable , Runtime ,
R untimeException , String , StringBuffer , Thread , Throwable
java.io I nputStream , IOException , OutputStream , Serializable
java.net InetAddress , ProtocolException , Socket , SocketException ,
S ocketInputStream , SocketOutputStream , UnknownHostException
spotless Beam , Bitmap , Component , Database , Event , External ,
ExternalException , ExternalManager , Field , Form , Graphics , IO ,
L abel , List , Lst , NativeIO , PButton , Spotlet
The JVM developed in the Spotless System consists of a central application that acts as a class
launcher, analogous to the Java command on the desktop. But in contrast to the desktop Java, it
includes a complete list of all available Java classes. It gives the user the ability to run any class
containing a static main method.
The JavaOne99 KVM Preview Version
At the JavaOne99 conference, some results of the Spotless project got their official place in the
Java family. The Java Technology was split into three categories: Java 2 Enterprise Edition (J2EE),
Java 2 Standard Edition, and the new Java 2 Micro Edition (J2ME). The heart of J2ME is a new
virtual machine, which is specially designed for embedded systems, cellular phones, and PDAs.
Because of its low memory footprint of only a few kilobytes, the new virtual machine was named
Kilobyte Virtual Machine (KVM). In fact, Sun did not merely announce the new technology; it
showed a preview version for PalmOS.
The new KVM was, as you may already have guessed, directly derived from the Spotless System
project. However, there are some changes in the supported package names, some classes are
canceled, and other classes are added (see Table 1.2 ) . It's still possible to browse through all
included Java class files, and all runnable Spotlet s that include a main method are now listed in
the PalmOS application launcher. The package spotless has been renamed com.sun.kjava ;
it now includes an enhanced version of the Palm-specific GUI classes.
Table 1 .2. Packages and Classes Included in the JavaOne99 KVM
Package Name I ncluded Classes
java.lang Class , Error , Object , Runtime , String , StringBuffer , Thread ,
Throwable , Exception , IllegalAccessException ,
IndexOutOfBoundsException , NullPointerException , Runnable ,
R untimeException
java.io InputStream , IOExceptopn , OutputStream , Serializable
java.net Socket , SocketException
com.sun.kjava Bitmap , Button , Caret , CheckBox , Database , Dialog ,
DialogOwner , Graphics , HelpDisplay , IntVector , List ,
RadioButton , RadioGroup , ScrollOwner , ScrollTextBox , Slider ,
Spotlet , TextBox , TextField , Trigonometric , ValueSelector ,
V erticalScrollbar
Note
This class overview is not intended to replace an API reference. It simply describes the
formation of the KVM packages and their classes compared with the Spotless System.
Beneath downsized versions of some standard Java packages, the first KVM contained some
Palm-specific GUI classes, mostly derived from the Spotless project. A short look at the size of