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by Mike Yawn,
Commercial Systems Division
A major new release of Java, Version 1.2.2, is included with
this release of MPE/iX. This article briefly describes some of the
changes. One change is the name; the former Java Developer's
Kit (JDK) is now called the Software Developer's Kit (SDK)
for Java. You will also find in the literature that SDK 1.2 is
frequently referred to as the Java 2 Platform. This is done merely
to emphasize the large increase in functionality over JDK 1.1.x
(which was presumably, although not explicitly, the Java 1 Platform).
The Java 2 Platform does not indicate an SDK version of 2.0. Feel
free to be confused by this.
This article does not attempt to cover all the new features
of SDK 1.2, of which there are hundreds. Instead, it covers a small
number of changes that are visible to the casual user. Programmers
wishing to take advantage of all the new APIs and features can obtain
a list at new features in the Java 2 platform at
http://java.sun.com/products/jdk/1.2/docs/relnotes/features.html.
Users just getting started with Java and wanting to learn
the language may want to reference the tutorial at
http://java.sun.com/docs/books/tutorial/index.html.
HTML format documentation was previously included as part
of the JDK release. Because of the amount of disk space consumed
by these files, they are now separately downloadable and installable
from CSY's Jazz web server. As a result, you have the option
of not installing the files at all, or of installing them on a different
system if you do not run web server software on your HP 3000. The
files can be downloaded from http://jazz.external.hp.com/src/java.
Navigate to the JDK 1.2 download page and select the
HTML Documentation Files package. You can also browse the documentation on-line
at http://java.sun.com/products/jdk/1.2/docs/index.html.
Previous versions of Java delivered for the HP 3000 included
a Motif implementation of the Abstract Windowing Toolkit (AWT).
The files comprising the AWT consumed a large amount of disk space,
and feedback indicated that few users found the Motif implementation
useful. We have discontinued distributing the AWT as part of our
Java offering. For applications that require AWT functionality,
the Remote AWT for Java technology from IBM can be used to allow
graphical applications running on the HP 3000 to have their graphical
displays redirected to a client system that also runs the Remote AWT
software. The Remote AWT software is available at no charge from
http://www.alphaworks.ibm.com/tech/remoteawtforjava.
As with previous Java versions, you must stream JINSTJDK.INSTALL.JAVA
to actually install the SDK on your system.
One minor but noticeable change in this release is in the directory structures
for the Java product. The top level directory is still
/usr/local/java/<version>/, with <version> being jdk1.2.2
in this release. As in previous releases, there are subdirectories
/bin and /lib at this level, containing binaries and libraries,
respectively. New at this level is a /jre (for Java Runtime Environment)
subdirectory, which is also subdivided into /bin and /lib subdirectories.
This change is transparent to users, who should still use
/usr/local/java/latest/bin as the location for executable programs.
Further subdivision has happened in the libraries hierarchy;
there is now a /classic subdirectory where the executable library
(XL) containing most JVM functionality resides. This is in preparation
for supporting multiple Java Virtual Machines running in the same directory
hierarchy in a future release.
Certain command line options to Java that have been supported
in previous releases are actually nonstandard, and not guaranteed
to be available on all VM implementations. To help identify such
nonstandard options, they now must be prefixed by -X. As
an example, the -verbose option is standard, and thus is
specified as -verbose on both 1.1.x and 1.2.x versions. -nojit
is nonstandard, so -nojit works on the 1.1.x releases,
but must be specified as -Xnojit on 1.2.x releases. Typing
java with no options or filenames causes a list of standard options
to be printed. Typing java -X causes a list of nonstandard
options to be printed.
Releases prior to JDK 1.1.7 included a JAVAUDC UDC file in
PUB.JAVA. In JDK 1.1.7, the UDC file was replaced by two command files
in PUB.SYS: JAVA (to invoke the JVM) and JAVAC (to invoke the javac
compiler). If you have previously installed a web download version of
JAVA 2 on your HP 3000, the installation will have created command
files named JAVA2 and JAVA2C in PUB.SYS. With SDK 1.2.2,
these files are no longer required and you can purge them. The JAVA and
JAVAC command files distributed with this release will work
correctly with both older JDK1.1.x versions of Java, and newer 1.2.x versions.
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