J2ME in a Nutshell

Name

Package java.util

Synopsis

The java.util package, whose class hierarchy is shown in Figure 13-1, contains several utility classes that are of general use, but not central enough to the Java language to be included in the java.lang package.

The Java 2 version 1.3 java.util package contains 54 classes and interfaces. By contrast, the CLDC version contains only 10 classes; MIDP adds another two for timer handling. As a result, these platforms have drastically reduced support for collections and internationalization. The CDC platform provides a much more complete implementation of this package, leaving out only 7 classes, and the Foundation Profile requires that all of the J2SE classes and interfaces be present. As with the other packages in this reference section, we won’t address the CDC and Foundation Profile versions here because the classes they contain are identical to those in J2SE. See Java in a Nutshell (O’Reilly) for more information.

The collection classes in this package are a subset of those available with JDK 1.1. All vestiges of the Java 2 collections framework have been removed. One consequence of this is that some classes have been reparented. Vector, for example, is derived from Object in CLDC rather than from AbstractList, as it is in J2SE. Other notable changes are the removal of the Properties class as well as the Dictionary class, the latter being the parent of Hashtable. In CLDC, Hashtable remains, but it is derived from Object instead.

CLDC retains the ...