Java Applets to JSP Conversion

[The One]

Hi

I am looking for a project to convert the existing JAVA applets into
JSP scripts. Basically I need to remove the Java Client requirements
on the user's machine and also move most of the processing work from
applets to servlet.

Let me know some steps to start with if anyone has experienced this
kind of project.

Thanks

 

[Andrew Thompson]

I am looking for a project to convert the existing JAVA

It is 'Java', not 'JAVA'.

...applets into
JSP scripts. Basically I need to remove the Java Client requirements
on the user's machine and also move most of the processing work from
applets to servlet.

Yeh, sure. Umm.. what do the applet's *do*?

As an aside. Why is it the applets are being phased out?
Java Web Start'ed apps. might be an altogether better option.

Andrew T.

 

[The One]

It is 'Java', not 'JAVA'.


Yeh, sure. Umm.. what do the applet's *do*?

As an aside. Why is it the applets are being phased out?
Java Web Start'ed apps. might be an altogether better option.

Andrew T.

Well

Basically its a web based online transaction processing system. The
application needs to remove the constraint for JAVA client because its
build in older java version 1.3 and many time clients just go for JAVA
updates and get the new version and some parts do not work. Also it is
very slow. That is why need to convert to JSP..

Thanks

 

[Owen Jacobson]

Well

Basically its a web based online transaction processing system. The
application needs to remove the constraint for JAVA client because its
build in older java version 1.3 and many time clients just go for JAVA
updates and get the new version and some parts do not work. Also it is
very slow. That is why need to convert to JSP..

Thanks

You're looking at a rewrite, not a conversion. The lifecycle and user
interaction models of applets and serlvet/JSP systems are not
fundamentally compatible with each other.

If the applet is relatively well-designed you'll be able to salvage
the core "business logic" part of the applet, but you won't be able to
reuse much, if any, of the UI code.

That said, it's odd that you've found that parts of an applet written
for 1.3 do not work under newer Java versions (1.5, 1.6). Can you
elaborate a bit on that?

 

[Andrew Thompson]

Owen Jacobson wrote:
...

That said, it's odd that you've found that parts of an applet written
for 1.3 do not work under newer Java versions (1.5, 1.6). ..

I find this odd, as well.

..Can you elaborate a bit on that?

Notes to the the OP:
1) This problem will probably be better solved by
using Java Web Start to launch the applet, rather
than converting the rich client to a JSP (/HTML)
based thin client.
2) Please stop SHOUTING at us. See my first
post for details.

--
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-general/200711/1

 

[The One]

You're looking at a rewrite, not a conversion. The lifecycle and user
interaction models of applets and serlvet/JSP systems are not
fundamentally compatible with each other.

If the applet is relatively well-designed you'll be able to salvage
the core "business logic" part of the applet, but you won't be able to
reuse much, if any, of the UI code.

That said, it's odd that you've found that parts of an applet written
for 1.3 do not work under newer Java versions (1.5, 1.6). Can you
elaborate a bit on that?

humm..

I thought there might be some work around for this conversion. Let me
know if anybody has some sort of tutorial or process that can explain
the process a bit. Certainly it depends on current implementation but
still some generic version of the process would be a good way to
start.


Frankly, the application is very old and java client shows error on
some parts of the system on newer JAVA versions. Also, sometimes when
user want to use this application they need to get a computer with
JAVA client installed.. I wish I have to just work on the part that is
not working on higher JAVA versions.. but unfortunately that's not the
case..

Thanks for the help.

 

[Lew]

I thought there might be some work around for this conversion. Let me
know if anybody has some sort of tutorial or process that can explain
the process a bit. Certainly it depends on current implementation but
still some generic version of the process would be a good way to
start.

There is none that I've encountered. You will note that Andrew pointed out that:

The lifecycle and user interaction models of applets and serlvet/JSP systems are not
fundamentally compatible with each other.

They are fundamentally different. Applets run in a JVM in the browser.
Servlets run in an application server on a server.

I don't think it's meaningful to speak of a "conversion" from applets to
servlets. They're as different as apples and oranges.

As Andrew pointed out:

You're looking at a rewrite, not a conversion.

Frankly, the application is very old and java [sic] client shows error on

It's "Java".

some parts of the system on newer JAVA [sic] versions. Also, sometimes when

It's "Java".

user want to use this application they need to get a computer with
JAVA [sic] client installed.. I wish I have to just work on the part that is
not working on higher JAVA [sic] versions.. but unfortunately that's not the
case..

You have been asked before. What part doesn't work on newer Java (not "JAVA")
versions?

Thanks for the help.

We could help more if you answered our questions.

Let's summarize:
- Going from applet to servlet is not a "conversion", it's a rewrite.
- Applets run just in a JVM, within a browser. Servlets run in an application
server.
- The language is spelled "Java". It's a proper noun.
- Java Web Start will likely solve the problems with your applets. It is a
conversion from applet to application and much less difficult than rewriting
as a servlet.
- What "part ... is not working on higher [Java] versions"?

 

[Owen Jacobson]

There is none that I've encountered. You will note that Andrew pointed out that:

^^^^^^

....

As Andrew pointed out:

^^^^^^

Oi!

We could help more if you answered our questions.

Let's summarize:
- Going from applet to servlet is not a "conversion", it's a rewrite.
- Applets run just in a JVM, within a browser. Servlets run in an application
server.
- Java Web Start will likely solve the problems with your applets. It is a
conversion from applet to application and much less difficult than rewriting
as a servlet.
- What "part ... is not working on higher [Java] versions"?

I have one more: Have you used any server-side programming tools
before? If so, which ones? It might help explain the difference in a
clearer way and it might help us suggest a useful path.

 

[Lew]

Oi!

Crap. Sorry.

As *Owen* pointed out, ...

With the two of you putting out such good advice I got confused.

I'm just glad you put a smiley on that.

Don't let me distract the OP from the questions *Owen* just asked:

 

[Andrew Thompson]

Oi!

Yes. Lew probably mistook your words for mine because
they were sensible words and I am commonly talking about
applets!

(My apologies if I've further stuffed the attributions.)

And to the OP -
1) please try and get 'Java' right. I have a whopping
hangover, and all this SHOUTing is hurting my head.
2) Java Web Start* can ensure both a perception of
fast start-up (I am not even clear on whether the issue
is 'start-up time' or 'processing time') because it manages
class caching**, and second and subsequent launches will
use the cached version. It is also the only realistic way
to handle Java Run Time versioning***. A single JNLP file
on the server, and to have the server configured to serve
the correct content-type for JNLP files - might be all it
takes to 'fix' the problem, or at least the most problematic
aspects of it.

* <http://www.physci.org/jws/#jtest>
** For even better control over caching behaviour.
<http://www.physci.org/jws/#ds>
*** <http://www.physci.org/jws/version.html>
<http://www.physci.org/jws/version.html#earlier>

--
Andrew Thompson
http://www.athompson.info/andrew/

Message posted via JavaKB.com
http://www.javakb.com/Uwe/Forums.aspx/java-general/200711/1

 

[The One]

Yes. Lew probably mistook your words for mine because
they were sensible words and I am commonly talking about
applets!

(My apologies if I've further stuffed the attributions.)

And to the OP -
1) please try and get 'Java' right. I have a whopping
hangover, and all this SHOUTing is hurting my head.
2) Java Web Start* can ensure both a perception of
fast start-up (I am not even clear on whether the issue
is 'start-up time' or 'processing time') because it manages
class caching**, and second and subsequent launches will
use the cached version. It is also the only realistic way
to handle Java Run Time versioning***. A single JNLP file
on the server, and to have the server configured to serve
the correct content-type for JNLP files - might be all it
takes to 'fix' the problem, or at least the most problematic
aspects of it.

* <http://www.physci.org/jws/#jtest>
** For even better control over caching behaviour.
<http://www.physci.org/jws/#ds>
*** <http://www.physci.org/jws/version.html>
<http://www.physci.org/jws/version.html#earlier>

Thank you guys for taking interest in trying to solve my problem. I
really appreciate it...


Let me talk more about the project which will get us all on one page:



The project I am working on is web-based online transaction processing
system. Yes, its a thick client architecture. The client part is
developed in Java Applets and servlets for server side processing.
Unfortunately, current design has more work(processing) done on client
side and very less on server side. Its one of the typical website with
lots of data going and coming. this makes the system very slow.

Also, the system was developed quite a time before on Java 1.3
version. This is the version with quite a problem in garbage
collection which makes the system to go run out of memory sometimes
(occasions are very very rare). Now, I tried to upgrade my Java client
to 1.4 but some of them modules do not work correctly. Meaning, some
of the screens do not work. They give JAVA version error.

Also, users of this system involves many people who need to access
system from home/work and they are not really computer guys. Meaning,
installing a JAVA client on users machine is the constraint we want
to remove.

So, we are planning to switch from JAVA applets to JSP and still using
servlets to do processing. Basic Goal is to make system efficient and
JAVA client Free..

I hope I made clear.

Thanks once again .. .

 

[Lew]

Also, the system was developed quite a time before on Java 1.3
version. This is the version with quite a problem in garbage
collection which makes the system to go run out of memory sometimes
(occasions are very very rare). Now, I tried to upgrade my Java client
to 1.4 but some of them modules do not work correctly. Meaning, some
of the screens do not work. They give JAVA version error.

It's not "JAVA", it's "Java". It's not "JAVA", it's "Java". It's not "JAVA",
it's "Java".

How about you cite the actual error instead of paraphrasing it? How about you
cite the code that gives the error, instead of hiding the information?

The thing that's weird is that nearly everything that works in Java 1.2 works
in Java 6. We've been asking and asking and asking what actually breaks.

If you ask for advice, you should answer the questions people are asking, and
spell the name of the language correctly.

 

[The One]

It's not "JAVA", it's "Java". It's not "JAVA", it's "Java". It's not "JAVA",
it's "Java".

How about you cite the actual error instead of paraphrasing it? How about you
cite the code that gives the error, instead of hiding the information?

The thing that's weird is that nearly everything that works in Java 1.2 works
in Java 6. We've been asking and asking and asking what actually breaks.

If you ask for advice, you should answer the questions people are asking, and
spell the name of the language correctly.

Thanks once again for curiosity..

Well here is the link that explains my error. Its a Java major/minor
version error.
http://www.jguru.com/forums/view.jsp?EID=1345467

And also the switch from Java Applets to JSP is already decided at
least to avoid the requirement to install Java client on user machine.
So, I think our focus should be on how to work on this switch.

I know you are really trying to help out to solve that java client
upgrade problem but I think it is out of scope now..

Thanks.

 

[Lew]

Thanks once again for curiosity..

Well here is the link that explains my error. Its a Java major/minor
version error.
http://www.jguru.com/forums/view.jsp?EID=1345467

That doesn't make sense. Generally, newer Java engines can run
earlier-version classes. It's the other way around that causes trouble.

I am also suspicious of information from someone who refers to "j2sdk1.5". If
they don't know what a version is called, how can you trust their advice about
versions?

Anyway, thanks for not answering the question. You know, this isn't a help
desk, it's a discussion group, and your refusal to discuss isn't appropriate.
We have questions, too, and if you're going to expect people to help you,
you must reciprocate.

Good luck with your next question.

 

[The One]

That doesn't make sense. Generally, newer Java engines can run
earlier-version classes. It's the other way around that causes trouble.

I am also suspicious of information from someone who refers to "j2sdk1.5". If
they don't know what a version is called, how can you trust their advice about
versions?

Anyway, thanks for not answering the question. You know, this isn't a help
desk, it's a discussion group, and your refusal to discuss isn't appropriate.
We have questions, too, and if you're going to expect people to help you,
you must reciprocate.

Good luck with your next question.

Unfortunately I can not share the code. Its a constraint and one more
constraint is that I have to do this switch from Java Applets to JSP.

I am not being rude but i think the focus should not be on why are
those constraints.. we should just try our best to solve the problem.


Thanks for you time..

 

[Lew]

I am not being rude but i [sic] think the focus should not be on why are
those constraints.. we should just try our best to solve the problem.

"We"? "We"?

It's your problem, bub. We are not a help desk, we are a discussion group.
You can't just dip in here for free advice and not contribute. We aren't here
to "solve the problem" for you. We're here to discuss the problem with you,
for *mutual* benefit.

I am not saying you have to share proprietary information. I am saying to get
off your high horse and not to treat us like your personal assistants.

 

[The One]

I am not being rude but i [sic] think the focus should not be on why are
those constraints.. we should just try our best to solve the problem.

"We"? "We"?

It's your problem, bub. We are not a help desk, we are a discussion group.
You can't just dip in here for free advice and not contribute. We aren't here
to "solve the problem" for you. We're here to discuss the problem with you,
for *mutual* benefit.

I am not saying you have to share proprietary information. I am saying to get
off your high horse and not to treat us like your personal assistants.

Yes.. Off course its my problem and I am gonna fix is .. just don't
know how right now. its a matter of time..

Anyway.. I can't understand what is not clear here.. I have to work on
this switch and you should just give your best ideas in that direction
only ..

So, please post here if you have some idea on the issue listed above..
anything else would be waste of your and my time..

Thanks once again.. and sorry for the Java mis-spell..

 

[The One]

I am not being rude but i [sic] think the focus should not be on why are
those constraints.. we should just try our best to solve the problem.

"We"? "We"?

It's your problem, bub. We are not a help desk, we are a discussion group.
You can't just dip in here for free advice and not contribute. We aren't here
to "solve the problem" for you. We're here to discuss the problem with you,
for *mutual* benefit.

I am not saying you have to share proprietary information. I am saying to get
off your high horse and not to treat us like your personal assistants.

Yes.. Off course its my problem and I am gonna fix is .. just don't
know how right now. its a matter of time..

Anyway.. I can't understand what is not clear here.. I have to work on
this switch and you should just give your best ideas in that direction
only ..

So, please post here if you have some idea on the issue listed above..
anything else would be waste of your and my time..

Thanks once again.. and sorry for the Java mis-spell..

Just found one more similar project going on here on a Getacoder.com

http://www.getacoder.com/projects/convert_java_applet_jsp_28069.html

Unfortunately, you have to create an account to see this problem.
Registration is free.

Thanks.

 

[Lew]

In other words, we should serve your needs and ignore ours.

In other words, you only want help, but not to contribute.