10.12: Developer's Kit for Java/iX

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Background

• This first release of Java/iX will be supported by the Response Center on a "best effort" basis.
• Performance has been a secondary concern to reliability in our engineering efforts up to this point. While Java/iX includes HP's own Just-In-Time (JIT) compiler which allows Java programs to be converted into native PA-RISC code at runtime, customers may find that the overall performance for some Java applications will be less at this time than on other platforms.
• This release of Java/iX does not pass 100% of the Java Compatibility Kit test suite, which prevents it from being officially labeled as 'Java Compatible' at this time.
• Sun is developing a functionality specification for Java running on server systems such as the HP 3000. It is likely that we will target this specification for the functionality to be included in future releases of Java/iX. Thus it is possible that some of the Java APIs which are not normally used in server-side Java programs, but which are included in the current Java/iX release, may not be supported in future versions.

Installing or Updating Java

Shell or CI?

• The MPE Command Interpreter will launch Java programs faster, because of the efficiency of MPE's CREATEPROCESS mechanism compared to POSIX fork() and exec().
• The POSIX shell provides intelligent default values for several environment variables, so the user does not, in most cases, have to provide values.

• SYSNAME
• PATH (or HPPATH)
• CLASSPATH
• LD_LIBRARY_PATH
• THREADS_FLAG
• DISPLAY

SYSNAME Variable

 shell/iX> export SYSNAME=hp3000
  

PATH (or HPPATH) Variable

 shell/iX> export PATH=$PATH:/usr/local/java/latest/bin
  

 :setvar HPPATH HPPATH+",/usr/local/java/latest/bin/PA-RISC/green_threads"
  

CLASSPATH Variable

 shell/iX> export CLASSPATH=$CLASSPATH: (add your stuff here)
  

 :setvar CLASSPATH "/usr/local/java/latest/lib/classes.zip:
  (add your stuff here)"
  

LD_LIBRARY_PATH Variable.

 shell/iX> export LD_LIBRARY_PATH=$LD_LIBRARY_PATH: (add your stuff here)
  

 :setvar LD_LIBRARY_PATH "/usr/local/java/latest/lib/PA-RISC/green_threads:
 (add your stuff here)"
  

THREADS_FLAG Variable

 shell/iX> export THREADS_FLAG=green
  

DISPLAY Variable

 shell/iX> export DISPLAY=sysname:0
  

 :setvar DISPLAY "sysname:0"
  

• Design the user interface as a separable module that can be executed on a client, and leave application logic and database access modules on the server.

Java Directory Structure

Using Java

Writing Java Programs

• The name must be followed by the extension .java
• The name is case-sensitive. While not a requirement, it is conventional to use mixed case in class names, with an initial capital and additional capitals used if the class name contains more than one word (for example, HelloWorld.java).
• Java files must be in bytestream format. VI will create bytestream files for you. If you use another editor such as HPEDIT, you will need to use the shell's tobyte command to convert the source file to bytestream format.

 public class HelloWorld
 {
     public static void main(String[] args) {
          System.out.println("Hello, World!");
          }
 }
  

Compiling a Program

 javac HelloWorld.java
  

Executing a Program

 java HelloWorld
  

Where to Go for More Information

• The Official JavaSoft home page http://java.sun.com is updated very frequently. Check here for new releases of add-on products, such as the Beans Development Kit (BDK), Java Workshop, or Java Web Server. On-line tutorials and reference documents are available, plus access to developer resources and a wealth of other information.
• The Home Page for Java on the HP 3000 http://jazz.external.hp.com/src/java contains the latest MPE-specific Java information and downloadable software.