Java Applet on Macintosh

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Johnny - 06 Jul 2007 18:21 GMT

Hi all:

I have a very simple Java applet which runs perfectly on Windows in IE, but
when I try to load it in IE on MAC OS 9, I get an error"

An Exception Occurred, ClassNotFoundException for TestApplet

Java Exception: java.lang.NullPointerException.

The Page hosting the Java Applet is being served from Apache, and the code
is:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
</HEAD>
<BODY>
<applet code="TestApplet.class" width=450 height=600>
</applet>
</BODY>
</HTML>

Can anyone offer any advice as to what I can do?

Signature

John.

http://mscrmguy.blogspot.com/

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Steve W. Jackson - 06 Jul 2007 19:03 GMT

> Hi all:
>
> I have a very simple Java applet which runs perfectly on Windows in IE, but
> when I try to load it in IE on MAC OS 9, I get an error"

[ snip ]

> Can anyone offer any advice as to what I can do?

Mac OS 9 is officially dead, though a great number of users still stick
with it. Its Macintosh Runtime for Java (MRJ) only supported Java
1.1.8, and adding Swing support (early Swing 1.1.1, IIRC) was possible
but not pleasant.

Bottom line: don't worry about an applet working for any Mac not
running some release of Mac OS X (unless you want to use only Java 1.1.8
or earlier). The earliest releases of Mac OS X included Java 1.3. Java
1.5 (aka Java 5) is now in widespread use in Mac OS X 10.4, and Java 6
is in the works as a "developer preview" -- it's unclear whether it will
be made available as a finished product for 10.4, or only with the
release of 10.5 coming in October.

= Steve =

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Steve W. Jackson
Montgomery, Alabama

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Johnny - 06 Jul 2007 19:50 GMT

Hi Steve:

Thank you for the reply....My wife has a G5 with Mac OS X 10.3.9, and I
cannot get the applet running on that either. I just get a red "X" on the
page. Since she ahs 10.3.9 I cannot upgrade to the JDK 5, but I used the JDK
v1.6. to build the applet. I guess maybe that's the problem? Do I need to
use an earlier SDK?

Signature

John.

http://mscrmguy.blogspot.com/

>> Hi all:
>>
[quoted text clipped - 19 lines]
>
> = Steve =

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Steve W. Jackson - 06 Jul 2007 20:02 GMT

> Hi Steve:
>
[quoted text clipped - 3 lines]
> v1.6. to build the applet. I guess maybe that's the problem? Do I need to
> use an earlier SDK?

Java 6 (1.6) is *only* available as a developer preview and probably not
available for 10.3.9 at all. But to get it, you'd need to join the
Apple Developer Community (ADC), which you can do for free with an
online membership.

In any event, since the Applet was done in 1.6, it won't work in any
lower release on *any* platform.

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Steve W. Jackson
Montgomery, Alabama

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Johnny - 06 Jul 2007 21:51 GMT

Hi Steve:

Ok, thanks. I compiled using v1.3.1 and it worked on OS X.

John.

Signature

John.

http://mscrmguy.blogspot.com/

>> Hi Steve:
>>
[quoted text clipped - 12 lines]
> In any event, since the Applet was done in 1.6, it won't work in any
> lower release on *any* platform.

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Roedy Green - 07 Jul 2007 05:49 GMT

On Fri, 06 Jul 2007 14:02:55 -0500, "Steve W. Jackson"
<stevewjackson@knology.net> wrote, quoted or indirectly quoted someone
who said :

>In any event, since the Applet was done in 1.6, it won't work in any
>lower release on *any* platform.

you need to use the -target option in compile to make it work on
earlier JVMS.

See http://mindprod.com/jgloss/javacexe.html
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Andrew Thompson - 07 Jul 2007 06:03 GMT

>On Fri, 06 Jul 2007 14:02:55 -0500, "Steve W. Jackson"
><stevewjackson@knology.net> wrote, quoted or indirectly quoted someone
[quoted text clipped - 5 lines]
>you need to use the -target option in compile to make it work on
>earlier JVMS.

As well as the '-bootclasspath' option to *guarantee*
that no members of post n.n version are used. -target
is simply a directive to denote the class file format that
is recorded, as I understand it.

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

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Roedy Green - 07 Jul 2007 07:14 GMT

>As well as the '-bootclasspath' option to *guarantee*
>that no members of post n.n version are used. -target
>is simply a directive to denote the class file format that
>is recorded, as I understand it.

for more details see http://mindprod.com/projects/jdkversion.html
and http://mindprod.com/jgloss/javacexe.html
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Andrew Thompson - 07 Jul 2007 08:25 GMT

>>As well as the '-bootclasspath' option to *guarantee*
>>that no members of post n.n version are used. -target
>>is simply a directive to denote the class file format that
>>is recorded, as I understand it.

...

>and http://mindprod.com/jgloss/javacexe.html

Oh yeah, sorry. I suppose the idea of putting the
full information at the link (the same link you posted
before my comment) was not to have to go into the
minutae of a complex subject. Note to self -
"Read the link content".

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

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Andrew Thompson - 07 Jul 2007 08:34 GMT

>>>As well as the '-bootclasspath' option to *guarantee*
>>>that no members of post n.n version are used. -target
>>>is simply a directive to denote the class file format that
>>>is recorded, as I understand it.
>...
>>and http://mindprod.com/jgloss/javacexe.html

>...Note to self - "Read the link content".

Now I have - I find the specific reference to
Eclipse, under the -target details, very odd.
That same sentence can apply to Netbeans,
JBuilder, TextPad or an Ant build file - not
just Eclipse.

But otherwise - good info. - as usual.

Signature

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

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Steve W. Jackson - 09 Jul 2007 14:29 GMT

> >>>As well as the '-bootclasspath' option to *guarantee*
> >>>that no members of post n.n version are used. -target
[quoted text clipped - 12 lines]
>
> But otherwise - good info. - as usual.

But none of this is applicable to the OP, who indicated that the system
which would not run the applet was Mac OS 9...

Signature

Steve W. Jackson
Montgomery, Alabama

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Andrew Thompson - 09 Jul 2007 14:39 GMT

>> >>>As well as the '-bootclasspath' option to *guarantee*
>> >>>that no members of post n.n version are used. -target
[quoted text clipped - 4 lines]
>But none of this is applicable to the OP, who indicated that the system
>which would not run the applet was Mac OS 9...

The way I understand it, it does. Indicated
elsewhere in the thread was that the machine
ran 1.1.8, but the source was being compiled
using 1.3.1.

Signature

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

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Steve W. Jackson - 09 Jul 2007 16:08 GMT

> >> >>>As well as the '-bootclasspath' option to *guarantee*
> >> >>>that no members of post n.n version are used. -target
[quoted text clipped - 9 lines]
> ran 1.1.8, but the source was being compiled
> using 1.3.1.

I was actually referring to the series of messages that both you and
Roedy posted concerning the Java console and numerous other things. The
fact is, that OS is defunct and no reliance whatsoever should be placed
on its even being able to use applets any longer. But, if great care is
taken to use seriously ancient code via the techniques outlined, it
*can* work...but it's not wise.

Signature

Steve W. Jackson
Montgomery, Alabama

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Roedy Green - 07 Jul 2007 05:48 GMT

>An Exception Occurred, ClassNotFoundException for TestApplet
>
>Java Exception: java.lang.NullPointerException.
>
>The Page hosting the Java Applet is being served from Apache, and the code
>is:

See if you can turn on a console so you can find out where you are
getting the exceptions.

see
http://mindprod.com/jgloss/runerrormessages.html#CLASSNOTFOUNDEXCEPTION

Put your class in a package and put the class files in a jar. It must
be in the same directory as the HTML page that invokes.
See http://mindprod.com/jgloss/applet.html

Make sure Applets in general are working by running
http://mindprod.com/japplets/wassup.html
--
Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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