Java Class

[goboenomo]

Im starting a Computer Science course at school
we're spending like 3/4 of the year working on Java..
any tips or hints.. or basics anyone could tell me?

[rizzix]

Tutorials are available in the tutorial section... http://www.compsci.ca/v2/viewtopic.php?t=9576

[goboenomo]

thx

[wtd]

Don't think that experimenting with other languages will somehow detract from learning Java.

In particular, languages which have interactive interpreters available. Makes a good way to quickly write throw-away code.

[rizzix]

yea he can try out beanshell in that case...

[wtd]

For basic concepts, most interactive interpreters will work, though Haskell might be a bit too far removed from Java in philosophy.

One serious problem I have with Beahshell for learning purposes is that it doesn't show the value of expressions.

For instance, something as simple as:

code:

1 + 3

I should be able to see the result of that expression. The interactive interpreters for Ruby, Python, Scheme, Haskell, SML, O'Caml,
Common Lisp, Pike, and others behave this way.

code:

insaneones@ubuntu:~ $ irb irb(main):001:0> 1 + 3 => 4 irb(main):002:0> exit insaneones@ubuntu:~ $ python Python 2.4.1 (#2, Mar 30 2005, 21:51:10) [GCC 3.3.5 (Debian 1:3.3.5-8ubuntu2)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 1 + 3 4 >>> insaneones@ubuntu:~ $ mit-scheme MIT/GNU Scheme running under GNU/Linux Type `^C' (control-C) followed by `H' to obtain information about interrupts. Copyright 2004 Massachusetts Institute of Technology. This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Image saved on Tuesday October 19, 2004 at 6:00:49 AM   Release 7.7.90 || Microcode 14.11 || Runtime 15.3 || SF 4.41 || LIAR 4.116   Edwin 3.114 1 ]=> (+ 1 3) ;Value: 4 1 ]=> (exit) Kill Scheme (y or n)? Yes Happy Happy Joy Joy. insaneones@ubuntu:~ $ ghci    ___         ___ _   / _ \ /\  /\/ __(_)  / /_\// /_/ / /  | |      GHC Interactive, version 6.2.2, for Haskell 98. / /_\\/ __  / /___| |      http://www.haskell.org/ghc/ \____/\/ /_/\____/|_|      Type :? for help. Loading package base ... linking ... done. Prelude> 1 + 3 4 Prelude> :q Leaving GHCi. insaneones@ubuntu:~ $ sml Standard ML of New Jersey v110.44 [FLINT v1.5], November 6, 2003 - 1 + 3; val it = 4 : int - insaneones@ubuntu:~ $ ocaml         Objective Caml version 3.08.2 # 1 + 3;; - : int = 4 # exit 0;; insaneones@ubuntu:~ $ clisp   i i i i i i i       ooooo    o        ooooooo   ooooo   ooooo   I I I I I I I      8     8   8           8     8     o  8    8   I  \ `+' /  I      8         8           8     8        8    8    \  `-+-'  /       8         8           8      ooooo   8oooo     `-__|__-'        8         8           8           8  8         |            8     o   8           8     o     8  8   ------+------       ooooo    8oooooo  ooo8ooo   ooooo   8 Copyright (c) Bruno Haible, Michael Stoll 1992, 1993 Copyright (c) Bruno Haible, Marcus Daniels 1994-1997 Copyright (c) Bruno Haible, Pierpaolo Bernardi, Sam Steingold 1998 Copyright (c) Bruno Haible, Sam Steingold 1999-2000 Copyright (c) Sam Steingold, Bruno Haible 2001-2004 [1]> (+ 1 3) 4 [2]> (exit) Bye. insaneones@ubuntu:~ $ pike Pike v7.2 release 580 running Hilfe v2.0 (Incremental Pike Frontend) > 1 + 3; Result: 4 Terminal closed. insaneones@ubuntu:~ $ gst GNU Smalltalk ready st> 1 + 3 ! 4 st> insaneones@ubuntu:~ $

[goboenomo]

wtd wrote:

For basic concepts, most interactive interpreters will work, though Haskell might be a bit too far removed from Java in philosophy.

One serious problem I have with Beahshell for learning purposes is that it doesn't show the value of expressions.

For instance, something as simple as:

code:

1 + 3

I should be able to see the result of that expression. The interactive interpreters for Ruby, Python, Scheme, Haskell, SML, O'Caml,
Common Lisp, Pike, and others behave this way.

code:

insaneones@ubuntu:~ $ irb irb(main):001:0> 1 + 3 => 4 irb(main):002:0> exit insaneones@ubuntu:~ $ python Python 2.4.1 (#2, Mar 30 2005, 21:51:10) [GCC 3.3.5 (Debian 1:3.3.5-8ubuntu2)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> 1 + 3 4 >>> insaneones@ubuntu:~ $ mit-scheme MIT/GNU Scheme running under GNU/Linux Type `^C' (control-C) followed by `H' to obtain information about interrupts. Copyright 2004 Massachusetts Institute of Technology. This is free software; see the source for copying conditions.  There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. Image saved on Tuesday October 19, 2004 at 6:00:49 AM   Release 7.7.90 || Microcode 14.11 || Runtime 15.3 || SF 4.41 || LIAR 4.116   Edwin 3.114 1 ]=> (+ 1 3) ;Value: 4 1 ]=> (exit) Kill Scheme (y or n)? Yes Happy Happy Joy Joy. insaneones@ubuntu:~ $ ghci    ___         ___ _   / _ \ /\  /\/ __(_)  / /_\// /_/ / /  | |      GHC Interactive, version 6.2.2, for Haskell 98. / /_\\/ __  / /___| |      http://www.haskell.org/ghc/ \____/\/ /_/\____/|_|      Type :? for help. Loading package base ... linking ... done. Prelude> 1 + 3 4 Prelude> :q Leaving GHCi. insaneones@ubuntu:~ $ sml Standard ML of New Jersey v110.44 [FLINT v1.5], November 6, 2003 - 1 + 3; val it = 4 : int - insaneones@ubuntu:~ $ ocaml         Objective Caml version 3.08.2 # 1 + 3;; - : int = 4 # exit 0;; insaneones@ubuntu:~ $ clisp   i i i i i i i       ooooo    o        ooooooo   ooooo   ooooo   I I I I I I I      8     8   8           8     8     o  8    8   I  \ `+' /  I      8         8           8     8        8    8    \  `-+-'  /       8         8           8      ooooo   8oooo     `-__|__-'        8         8           8           8  8         |            8     o   8           8     o     8  8   ------+------       ooooo    8oooooo  ooo8ooo   ooooo   8 Copyright (c) Bruno Haible, Michael Stoll 1992, 1993 Copyright (c) Bruno Haible, Marcus Daniels 1994-1997 Copyright (c) Bruno Haible, Pierpaolo Bernardi, Sam Steingold 1998 Copyright (c) Bruno Haible, Sam Steingold 1999-2000 Copyright (c) Sam Steingold, Bruno Haible 2001-2004 [1]> (+ 1 3) 4 [2]> (exit) Bye. insaneones@ubuntu:~ $ pike Pike v7.2 release 580 running Hilfe v2.0 (Incremental Pike Frontend) > 1 + 3; Result: 4 Terminal closed. insaneones@ubuntu:~ $ gst GNU Smalltalk ready st> 1 + 3 ! 4 st> insaneones@ubuntu:~ $

wait....
what is that?

[goomba]

wtd is just showing examples of different languages that have interactive modes, which means that you can type in commands at a prompt and get immediate output, compared to Java where you have to properly set up a class file, compile and run it. Interactive mode are definitely very useful, but you shouldn't worry about them if you are only focusing on Java since they basically don't apply.

When you learn Java, try to apply Object Oriented concepts whenever possible, even if they seem unnecessary, redundant, or a waste of code. If you get into the habit of keeping code encapsulated properly in methods and classes, making bigger programs will be much easier for you. Don't write Turing in Java!

[wtd]

goomba wrote:

wtd is just showing examples of different languages that have interactive modes, which means that you can type in commands at a prompt and get immediate output, compared to Java where you have to properly set up a class file, compile and run it. Interactive mode are definitely very useful, but you shouldn't worry about them if you are only focusing on Java since they basically don't apply.

Interactive interpreters aren't as important in the Java world because for the most part they aren't there. Java programmers can't come to love the interactive interpreter that doesn't exist.

Yet, if they're not important, why do we have Beanshell, Groovy, Jython, JRuby, etc.?

[goomba]

Since they aren't "natively" part of Java, 3rd party interactive shells should be left to more advanced Java coders who already know how to program in Java without them.

Obviously there's the demand for these Python emulation layers, but then again Java leaves much to be desired in pretty much ANY area compared to Python and friends.