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PROBLEMS SOLVING
FAQ
System Requirements:
Java™ technology is supported by:
Netscape versions 2 and higher, MS Explorer versions 3 and higher; HotJava™ and
other browsers, on 32 bit operating systems (Windows 95/NT, Mac OS, Sparc,
Linux, etc.). Java™ technology applets will not appear on Windows 3.1, or on a 16 bit
browser (Netscape 4 for Win 3.1 supports Java™ technology but not as well as on Win 95). The
Java™ technology support should be enabled in the browsers too, otherwise you will see a
message stating your browser does not support Java™ technology. The Anfy wizard
requires Win 95/98/NT.
Differences between Java™ technology and
Javascript™
Java™ is different from
JavaScript™: Java™ is made by creating .class files and is more powerful than
JavaScript™ (which is a script/batch language written directly inside a .html
document). The Anfy package contains only Java™ technology applets.
How to add Java™ technology applets to
html documents:
1) Copy the .class
files to the same directory as the .html files, along with any GIF and JPG
images. In Anfy wizard this can be done with the "Copy all files to"function.
2) Add the <applet> tag in the html
document. Some html editors do not allow this or have special standards. If this
occurs, save the .html file first, then edit it with dos edit, notepad or other
ASCII text editor. Then manually add the <applet> tag. Anfy wizard helps you create the <applet> tag with the right parameters for
your purposes and your images, but you still have to copy and paste the
resulting <applet> tag in your html document. You can use the "Copy
all files to" function to save a html document that contains only the
applet, and then re-open it with your preferred html editor to add what you
want.
3) Upload the .html file, .class files and any others
(images etc.) to your web page directory as usual. Please note that you have
to upload the .class files using FTP in BINARY mode and not in ASCII mode !!
Otherwise the applets will not work (a "java.lang.ClassFormat"or "java.lang.MethodVerification" or "Bad Magic
Number" error message will be displayed). Be sure file names and
file length is not changed during the upload process: if files are of different
size, or have a different name ( example: the file ends with .cla instead of
.class) then something went wrong.
Most common errors:
A) LONG FILENAMES
TRUNCATION AND LETTER CASE CHANGE: Many MS-DOS users are still using PKUNZIP
to decompress zip archives or 16 bit programs to copy and upload files, and do
not take into consideration the difference between FiLe.ExE, FILE.EXE and
fILe.eXe. This is not good for various reasons:
The first one is the use of long file names: msdos (and old 16
bit win 3.1 programs) are only able to support file names with 8+3 characters. Newer
systems on the other hand support long file names, for example
MyNiceApplet.class, which has a suffix of 5 chars. If you use PKUNZIP to unzip
the applet archives, or upload the .class files on the server with an old
Windows 3.1 FTP program or similar, you will TRUNCATE the filename, and the
result will be MYNICEAP.CLA !
Trying to run the applet will result in a "java.lang.ClassNotFound"error displayed. Ensure you unzip using "winzip 32" or similar in
win95, and to copy/upload the files with these newer programs that do not
truncate the filenames.
Consider the case of the characters, as well, since many servers on
the Internet (Unix) are case sensitive. For example, if the applet
is named "MyNiceApplet.class" and you write "Myniceapplet.class",
the applet will not work. The most common mistakes are in mismatched image
filenames, because win95 is not case sensitive and it loads an image even if the
case is different.
For example, if you save an image as "image1.jpg" you will also
be able to load it from your local harddrive if you refer to it as IMAGE1.JPG,
image1.JPG or IMAGE1.jpg. But once you put it on your ISP's server it will only
work if you refer to it as image1.jpg.
Ensure the names of images you load from an applet are identical in case
and characters.
B) Wrong image or applet size: read the instructions for the
applet carefully because images usually MUST be of fixed sizes (for example
64*64, 128*128 etc.). Do not enlarge the applets too much, and images more than
a width of 600 pixels. They will not be fully visible to those using a video
mode of 640*480 pixels.
In most cases, Anfy wizard can detect an incorrect image or applet
size, and this will help prevent one of the most common errors.
Less common errors:
A) "Using
Netscape Gold 3, the applets work offline but fail to work online, displaying a
java.lang.NullPointerException error."
This is a bug in
the browser that randomly appears. If this occurs, try reloading, clearing the
cache, or in rare cases deleting the cache files manually from netscape cache
directory. Similar "NullPointer" error messages happen occasionally on
Netscape 4.04.
However, visitors will have no problems seeing the applet.
B) "I updated all the class files on my GEOCITIES
site, and when I reloaded the page I received an error message (java.lang.NoClassDefFoundException)
in applets".
This is a temporary problem generated by Geocities
and some other sites. If you reload the page after a couple of minutes, the
applets will run correctly. In other circumstances, this error means you
forgot to upload some .class files (for example anfy.class).
C)
"Using Netscape 3, I received an error message (java.awt.image.Memory
ImageSource: method newPixels(), or java.lang.NoSuchMethodError:
java.awt.image. Memory ImageSource) about the applets".
This
is a problem related to anfy.class. You are probably using an old or incorrect
anfy.class file, or you have an old one in the cache. Check and see that you
are using the same anfy.class that came with the applets, and clear the cache.
D)
"I am using the
AOL browser, and everything else on page would appear but the applet.
Instead there was a message -Loading image-, and the image never appeared, just
a gray rectangle".
In this case, you have to turn off graphics compression in the AOL
internet browser preferences as follows:
On the AOL Toolbar, click Members, Click Preferences, Click WWW Icon
(Picture of world globe), and you will see a dialog box. Click the "Web
Graphics" tab, and a page appears with the question "Do you want Web
Graphics to be compressed. This will display pages faster". Under the
question is a box that you "check" if you want compression, otherwise
leave it blank. If it is checked, clear it.
E) "I am
using a transparent gif image in one applet (lens, water, lake, etc.) as
main image, and I see gray background instead of transparency".
This
is because a transparent background is not supported in Java™ technology. You can
use transparent images ony as overlay images.
F)
Strangely, sometimes the GIF overlay images are not totally draw by
Netscape, but are draw completely when one uses Explorer.
In most
cases, you just have to re-save the GIF image in interlaced mode if it was
in normal mode, or vice-versa, then it will be displayed correctly. This
problem occurs more frequently on larger images.
G) "I
removed the <param name="credits" parameter, and the applet
is not running any more, even if it is registered".
With
registration, you purchase a regcode that enables link parameters and removes
the credits window that pops up when the applet is clicked. This does not
include the "credits" parameter. It is only a signature of the applet,
not visible by the visitors (except those who look at the page source code).
This is why it is not modified by your registration. Why would you want to
remove it? If you read the instructions carefully, then you should note that it
should not be removed.
Tips & Tricks:
1) You may be
thinking, "What will people without Java™ technology browsers see instead of
the applet ?" You can specify an alternate text, image, or a whole html
segment to be used instead of the applet:
<applet code="MyApplet.class" width=150 height=150> <param
name=param1 value="1234"> <param name=param2 value="5678"> <IMG
ALT="*" ALIGN=center SRC="alternateimage.gif" border=0> </applet>
You
can even load images for applets from a cgi-bin/ dir, maybe a 'pic of the day'
cgi or similar.
<applet code="MyApplet.class" width=150 height=150> <param
name=image value="/cgi-bin/Image.cgi"> <param
name=param2 value="5678"> <IMG ALT="*"ALIGN=center SRC="/cgi-bin/Image.cgi" border=0> </applet>
So,
you can display a normal image if Java™ technology is not present, rather than Java™ technology
manipulations of the image if Java™ technology is present. In the Anfy wizard, you can
enter this alternate text or html in the "For no Java™ technology browser" field.
2)
If you want to read .class files from another dir or path, just use the codebase
tag.
<applet codebase="http://www.app.com/app/" code="MyApplet.class"width=150 height=150> <param name=param1 value="1234"> <param name=param2
value="5678"> Sorry, your browser doesn't support Java™ technology. </applet>
3)
When you try to use a mask for the applet, there is a thin (about 1-2 pixel)
border at the top of the applet before the round image.
To remove it,
use the
HSPACE="0" and VSPACE="0" tags, within the
<applet> tag:
<applet code="MyApplet.class"hspace=0 vspace=0 width=150 height=150>
Frontpage users:
Here is an example of the
configuration steps for the Anfy Water applet:
1) If you don't already have an image, use Image Composer (
FrontPage's Tool ) to create and save an image as "water.gif" for
example, in a new empty folder.
2) In the Anfy wizard main screen, select WATER, press
the NEXT button, then press "browse" button and choose your image for
the effect. Then press the NEXT button 4 times, and use the publish function "Copy
all files to" to save all the needed files in the new folder.
3)
Open FrontPage. In FrontPage Explorer, import the Applets,
including anwater.html, anfy.class, AnWater.class , Lware.class, and
waterscr.txt. In other words, these files must be present in same folder
(directory) as the html document you will edit.
4) In
FrontPage's Editor, open anwater.html, then select the applet and click
copy button on the toolbar.
5) Open a new web page, or the document where you want to
insert the applet, and click the paste button on the toolbar.
A faster way would be:
4) Open FRONTPAGE.
5) Open the web page you want.
6) Drag the file to the open web 7) Click on the web page
within the editor. It will open with the applet in place, and you can go about
editing. Click on the JBAR in the applet to adjust the settings.
This
should configure the applet to work. If you want to change parameters, double
click the applet, and you can open "Java™ technology Applet Properties" box. You
may have directory problems on the server, because FrontPage requires a web
server and forces you to import the .class libraries onto the web.
If you copy them into the web directories, then you have to put them in the
right place and select "Recalculate Hyperlinks" in the explorer. Then
you have to make sure the applets parameter point to the applet properly.
Note: In order to change the scrolltext, you have to modify the
waterscr.txt content
Bug reports:
- Don't save .JPG
images from Adobe PhotoShop 4 with "thumbnail" option enabled,
because some Java™ technology implementations (Netscape 3) will not be able to read them.
Disable thumbnail feature or use PhotoShop 3.
- MS Explorer 3.02 (and some beta 4.0 versions) have a bug
that causes an exception: com.ms.applet.Security.Couldn`t connect when
Java™ technology loads images from the local Hard Disk.
Applets will work when you are online, but will be hard to test offline, so
get a newer or older version (3.01 or 4.0 final for example).
The URL for Java™ technology explorer upgrade is
http://www.microsoft.com/java/vm/vmdownload.htm.
Compatibility parameters:
PREFACE: Many people
think Java™ technology is dangerous, not secure, and crashes a lot of browsers. This is true
for poorly programmed applets and pages overloaded with 10 applets, and on old
computers. If you use Anfy applets with "Optimize for
compatibility" settings, placing NO MORE than one applet each html page, no
browsers will have the opportunity to crash.
What do I do if the
Java™ technology APPLET(s) uses 100% of my CPU power, slows down the browser, or steals all
my available memory ?
A) When the applet is running, Netscape or Explorer may
slow down, and sometimes the Operating System (Win95, WinNT, MacOS etc.)
hangs or slows down as well.
If this happens you have to increase the MinSYNC parameter
until the system operates normally. This value is usually set to 10, but you can
set it to 20,40,60,100 or even more to lower the applet speed and thus leaving
CPU power to the browser and OS. You can also decrease the "priority"parameter.
B) When the applet has been running for a short
period of time memory runs out and the hard disk starts spinning (the OS
is using it's swap file to simulate more memory).
If this happens, you are most likely using a version of Netscape 3 /
MS Explorer 3 w/bugs. This problem is not present in the fixed rel. 3 and rel.
4, but you can fix the problem by decreasing memdelay to 10 - 16:
Anfy wizard provides 3 predefined settings in the expert mode
panel:
Standard settings will set MinSYNC to 10 and priority to 3, and this is
acceptable for 99% of browsers.
If you want to ensure the applet will
run even in buggy versions of Explorer and Netscape and you don't care if the
applets run much slower, select the Optimize for compatibility option.
This will set MinSYNC to 30, priority to 1 and memdelay to 15.
If you
want to pump the applets to the max, and don't care if this will hit older
browsers and slow their CPU dramatically, select Optimize for speed.
This places a MinSYNC value of 2 and a task priority of 6.
It is
possible to manually set MinSYNC to 0 and priority to 10, for those who want to
test the applet in full speed on a P200MMX or Pentium II.
Remember, the
most important guideline:
DON'T INSERT MORE THAN ONE APPLET ON EACH
PAGE
If you really MUST place more than one applet per page (do so
at your own risk!), be sure to set the priority parameter to 5 on all applets.
If you want one to run faster than another, change their priority to match your
desired speeds.
You have another problem?
If you are a registered
Anfy user (in other words, if you purchased at least one regcode) and
you are experiencing a technical problem not described in this document, you may
freely ask for help to
Anfy Contact Persons.
Note:
The free support (in English only) is guaranteed only to registered users,
and please be sure to read the PROBLEMS SOLVING FAQ carefully. Most
common problems have already been answered.
Anfy
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Copyright © 1997,98,99 Fabio Ciucci. Java™ and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. Fabio Ciucci is independent of Sun Microsystems, Inc.
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