JAVA

• How do I start?
• References (FAQs, applets etc.)
• Writing Compilers in Java

How do I start?

To run your first applet, using Netscape browser

• Enable Java
  Netscape 2.02: -> Options -> Security Preferences -> ?
  Netscape 3.0b: -> Options -> Network Preferences -> Languages
  Personally, I am still paranoid about Java/JavaScript security, so I disable them most of the time and only enable them if I am somewhere I trust.
• set your CLASSPATH The latest versions of JDK1.1 say you must UNSET this variable when you use them! Don't confuse JDK with the browser.

  	setenv CLASSPATH /usr/webtools/netscape3/java_30
  	/usr/webtools/netscape &
  

  or use softlinks (but this doesn't work anymore)

  	cd ~/.netscape
  	ln -s /usr/webtools/netscape202/moz2_02.zip moz2_02.zip
  	ln -s /usr/webtools/netscape3b/moz3_0.zip moz3_0.zip
  

  Remember to redo this each time you go to a new version of the browser
  Steve Douglas wrote: there are two versions of Netscape in the dept, Netscape 3 and Netscape Gold 3. Each has a different collection of Java classes, you need to set your CLASSPATH variable to point to the right one.
• go to e.g. javasoft and try some of the applets there (e.g. the financial demo). I really like Sorting
• "If you turned Java off, then tried to open the Java Console from the Options menu [and nothing happened], then turned Java on again, you need to exit the Netscape browser and restart in order to make Java work."

How do I make my own applets?

• The language
  
  • The Java Tutorial - A practical guide for programmers Object-Oriented Programming for the Internet (Java Series) by Mary Campione and Kathy Walrath, from Addison Wesley. (local copy)
  • Brewing Java: A Tutorial The Java Developer's Resource by Elliote Rusty Harold from Prentice Hall.
    The tutorial is 215K, so here is an (older version) local copy
    the various applets etc from this tutorial
  • Java in a Nutshell
    contains errata (errors, clarifications, examples, etc.) and example programs
    It also points to Author's homepage for 'Exploring Java' containing lots more examples.
  • Teach yourself Java in 21 days is available online with further information
  • EckelOBJECTives - javabook
  • tutorials on many subjects by Dick Baldwin
• Software to compile & run it
  • Sun's JDK (Java Development Kit):
    • Linux JDK
    • Jave for Windows3.1? (Select "ADK for Win 3.1" from the menu to the right of the "downloads" icon, and then click on "download" for more info)
      AEK says: I downloaded a copy (almost 3Mbyte). I also needed a more recent version of Win32s (another 3Mbyte, almost). It crashes frequently and is [not fast]. I couldn't recommend its use for our students. Certainly not the current release.
    • Suns: you need to use Solaris.
      On our network, look in /appl/webtools on a Solaris machine.
    status of Java ports for SunOS4 and Linux
    johns@cs.man.ac.uk (John Sargeant) Fri Oct 03 11:49:52 BST 1997 wrote "The Java Development Kit is in /usr/webtools/jdk1.1 on the teaching systems. There is online documentation at http://www.cs.man.ac.uk/csonly/jdkdocs/ The main commands you need are 'javac' to compile programs and 'java' to run (interpret) them. The jdk also contains an appletviewer to view applets. These are in /usr/webtools/jdk1.1/bin Beware that it's *very* slow on most of the teaching Suns."
  • Java Open Language Toolkit includes the GuavaC Java compiler and the Kaffe bytecode interpreter.
  • Unix LiveConnect SDK supposedly includes a Netscape javah for unix (OSF/1)
    Later correction: You'll have to download the Windows version, and copy the generated files to a Unix system (they should be cross-platform).
  • how to use Netscape to compile Java. (from Java Tips - see below)
    Mike Lamb writes: In Netscape you can reload the java class file by holding the shift key and clicking on reload. Another useful method is to disable java from the options->security preferences menu, and then re-enable java support. For a more in depth explanation of reloading applets in netscape look at javaworld tips
  • JCC - Java to C Converter JCC is a direct Java to C translator. Unlike other translators JCC does not convert Java class files, but instead processes Java source code directly. It converts whole programs at a time, which can cause the conversion process to be quite lengthy, but has the advantage that a number of optimisations can be performed that would be very difficult to achieve with other techniques. When used with a good optimising C compiler it produces programs that are typically between 10 to 20 times faster than the 1.0.2 JVM. One example sort program has been speeded up 55 times.
  • "Harissa" is a system that includes a java-to-C translator. It can freely mix byte-code interpretation and compiled code. For information, including papers (COOTS '97) and instructions to download the system, see http://www.irisa.fr/compose/harissa Links to other similar systems such as Cecil/Vortex, Toba and the Java compiler by OSF are listed there as well.

You might also want to know about the Java mode for emacs:
java support is built in to the latest version of the C support cc-mode. All you have to do is switch to the latest version of emacs. This is currently installed as emacs19.31
If you are using the emacs (19.31) java support and want font-lock keywords for highlighting, just add (require 'java-f-lck) to your .emacs.
The easiest way to globally turn on font-lock support is to use something like

;; run font-lock on all files
;; *New with Emacs-19.31*  Turn on font-lock mode automatically
;; in all modes which support it.
(global-font-lock-mode t)
;; Enable the pretty colors
(setq font-lock-maximum-decoration t)

gdg writes: The Linux machines are currently running emacs19.30, which does not have sensible Java editing support. I have set up a mechanism to enable users to pick up the necessary code from a more recent emacs. To use this, just put the following in your .emacs
(load-file "/home/ta5/staff/graham/elisp/java-setup.el")

JAVAR is a prototype restructuring compiler that can be used to make implicit parallelism in Java programs explicit by means of multi-threading.

References (FAQs, applets etc.)

Java at Sun -> FAQs etc., including javasoft applets
java links
Java Notes
java book reviews
Java at Yahoo
Java FAQ
Java Tips
comp.lang.java Newbie FAQ
Java UK Experience

Local references

John Sargeant's pages about local Java information [local] and Java the language.

Writing Compilers in Java

JLex = lex for use with Java (used to be called JavaLex and live here) now associated with
"Modern Compiler Implementation in Java" by Appel, which also has links to:
JavaCUP = Java based Constructor of Useful Parsers, an LALR parser generator for Java.

regular expression package in Java

JavaCC (docs) (FAQ) is the Java Compiler Compiler, an LL(k) parser/lexer generator, generating Java code (originally known as Jack). It comes with C++, C, Java, HTML, IDL, and a bunch of other grammars. It comes with JJTree, a parse tree generator.

ANTLR 2.0 supports Java (now moved to www.ANTLR.org)

A compiler written in Java, not using JLex nor JavaCup.

MUSKOX v4.0 annotates C++ & Java classes and interfaces with EBNF LR(K) grammars. It features grammar inheritance and redefinition of rules. It also supports multiple parsers, recording/replay of trace logs, and HTML pretty-printing. Default and user-defined lexer and error processing is available. In addition, the new version provides syntactic lookaheads, semantic predicates, and syntax trees.

Free yaccable java grammar Updates (long overdue) include 1.1 extensions

Janusz Szpilewski (szpilews@priv.onet.pl) wrote on 14/Nov/1997 about JVM:
JVM is an emulator of a low level environment. But it is quite different than the existing hardware microprocessor systems. Besides the standard sets of instructions and registers, it offers support for managing objects, arrays, method invocations, global and local variables and some basic data types (mainly those that appear in Java). But there are also some limitations like that there is no direct access to the addresses of variables nor to the references to objects. This feature makes a fully functional implementation of C pointers rather an impossible task. [Therefore], compilers of some languages can be better implemented for the JVM than some other ones. Among successful implementations there are compilers of Prolog, Lisp, Logo and Basic.
A list of existing compilers and interpreters for the JVM points to:
the JVM specification
Jasmin - Java Assembler Interface for the JVM (GNU license) or Jasmin used for (book) "Java Virtual Machine" by Troy Downing and Jonathan Meyer from O'Reilly. (also see)
Javaa - Java Bytecode assembler
Jas - java bytecode assembler

Java version of Coco/R, an LL(1) compiler generator. (book)

A list of packages for compiler construction with Java

Java in the Curriculum