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Contents
Java Plug-in Software Basics back to top
Q: What is the Java Plug-in Software?
A: Java Plug-in Software is a software product from
Sun Microsystems, Inc.
that allows enterprise web managers to direct Java applets and
JavaBeans components
on their intranet web pages to run using Sun's Java Runtime Environment
(JRE).
Q: Is Java Plug-in 1.2.2 included in the Java 2 Software
Development Kit (SDK), Standard Edition v 1.2.2?
A: Yes, new in this release is the inclusion of Java
Plug-in 1.2.2 Software as part of the Java 2 Runtime Environment,
Standard Edition (JRE) 1.2.2 for Microsoft Windows Production Release.
In turn, JRE 1.2.2 is included as an optional installation of the Java
2 SDK, Standard Edition v 1.2.2 Microsoft Windows Production Release.
Q: Can Java Plug-in 1.1.x Software and Java Plug-in
1.2 Software co-exist on the
same system?
A: No. Java Plug-in Software for Internet Explorer
shares the same CLSID
between 1.1.x and 1.2. Similarly, Java Plug-in Software for
Navigator shares a
set of MIME types between 1.1.x and 1.2. As a result, installing
Java Plug-in 1.1.x Software and Java Plug-in 1.2 Software on the
same machine may result
in one version being overwritten.
We strongly recommend that users do the following when
upgrading Java Plug-in Software:
- Install Java Plug-in 1.2 Software in the same directory as
Java Plug-in
1.1.x Software or
- Uninstall Java Plug-in 1.1.x Software before
installing Java Plug-in 1.2 Software
Notice that installing Java Plug-in 1.1.x Software after
installing Java Plug-in 1.2 Software on the same machine is not
recommended.
Q: Can I freely redistribute Java programming language
applets and applications for Microsoft Windows
developed using the Java 2 SDK, Standard Edition v 1.2.2?
A:Yes, but you need the appropriate redistribution
license found only
in the standalone JRE 1.2.2 download. The JRE included as part of the
Java 2 SDK, Standard Edition v 1.2.2 does not allow for redistribution
of applets and applications that
use the JRE 1.2.2 and Java Plug-in 1.2.2 Software. In order to
redistribute a Java
application or applet, you must download and use the standalone JRE
1.2.2
that includes the appropriate redistribution license terms.
Q: Where is Java Plug-in Software for Solaris Production
Release?
A:
In an effort to better serve the Solaris community, Sun Microsystems
offers a tuned and supported version of Netscape Navigator and Java
Plug-in Software for Solaris. Follow this link for more information and
downloading: http://www.sun.com/solaris/netscape
Q: Does the Java Plug-in Software work on platforms other
than Microsoft Windows
or Solaris (for example, Mac OS, AIX, Linux, HP-UX, etc.) versions of
IE or Navigator?
A:
For information about support for Java Plug-in Software on other
operating systems, please contact the operating system provider.
Q: For whom is the Java Plug-in Software intended?
A: The Java Plug-in was designed for enterprise
customers
who wish to deploy Java 2 SDK, Standard Edition v 1.2.2-based applets
on their intranet web pages, and
support Microsoft Windows- and Solaris-based browsers in their
enterprise.
Q: Is there documentation available for Java Plug-in
Software?
A: To assist in your deployment of Java Plug-in
Software, Sun has made
available a variety of technical
documentation. Documentation regarding the HTML
specifications, using Java Plug-in Software in intranet environments,
how proxy
configuration works, how to script applets, and much more are available
from the Java Plug-in Software documentation page.
Q: What information should I provide when reporting a bug
to http://java.sun.com/cgi-bin/bugreport.cgi
A: When reporting bugs against Java Plug-in Software,
always include the following information:
- Operating system, including version number
- Web browser, including version number
- Complete output of the Java Console window
- Network configuration information--proxy, special intranet
environment,
etc.
- Complete description of the failure/problem encountered.
Please
delineate
the steps taken to reproduce the problem, one-by-one.
Features and Benefits back to top
Q: What features does the Java Plug-in Software offer?
A: The Java Plug-in Software delivers several key
capabilities
to enterprises using Internet Explorer or Netscape's Navigator on Win32
and Solaris desktops:
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Full Java 2 SDK, Standard Edition v 1.2.2 support |
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Full Java Compatible support |
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Future-ready architecture |
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Free public download and easy install |
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Free Java Plug-in HTML Converter |
A complete list of the features
of the Java Plug-in 1.2 HTML Converter are also available from the Java
Plug-in Software documentation
page.
Q: What is the advantage of downloading and using the Java
Plug-in Software
rather than the browser's default Java virtual machine?
A: Using the Java Plug-in allows enterprises to:
- Take full advantage of Java 2 SDK, Standard Edition v 1.2.2
functionality such as JavaBeans, JNI, and
RMI today.
- Develop and deploy 100% Pure Java applets on Internet
Explorer and
Netscape Navigator browsers, and be assured that
they will run reliably and consistently in both browsers.
- Be assured that they will receive support for the latest
releases of
Sun's
Java 2 platform --including the high-performance Java HotSpot virtual
machine--in Internet Explorer and Navigator as soon as Sun releases
them.
Q: Can I set up the Java Plug-in Software to download from
an intranet web server (behind a firewall), rather than downloading it
from Sun's web site?
A: Yes. For more information, see the Guide to Using Java
Plug-in Software in Intranet Environments and the Java Plug-in
Software documentation
page.
Q: Does the Java Plug-in Software provide support for
Netscape Navigator?
A: Yes. The Java Plug-in Software supports Netscape
Navigator 3.0 and later on Windows
95 and 98, Windows NT 4.0, and Solaris 2.5 and 2.6-based systems.
Q: Does Java Plug-in Software support scripting?
A: Java Plug-in Software supports scripting of applets
in Internet
Explorer. However, such scripting is not available when using Java
Plug-in Software in Navigator. Because of limitations in Netscape's
plug-in API,
scripting cannot be supported directly (through LiveConnect) in
Navigator.
We are working closely with Netscape to address this issue in a
future release of Navigator.
Q: Does the Java Plug-in Software include a just-in-time
(JIT) compiler?
A: Yes. The Win32 edition of Java Plug-in Software
includes the
latest Symantec JIT 3.0 compiler.
Q: What version of the Java 2 SDK, Standard Edition does
the Java Plug-in Software support?
A: The Java Plug-in Software features a future-ready
architecture
that makes it easy for Sun to bring the latest Java 2 SDK, Standard
Edition features and functionality
to Windows and Solaris desktops. The 1.2.2 release
of the Java Plug-in Software incorporates JRE 1.2.2, the most recently
completed
version of the JRE available.
Q: Does the Java Plug-in Software offer support for all the
features
in Java 2 SDK, Standard Edition v 1.2.2?
A: Yes. The Java Plug-in Software uses the same JRE
that users
can download from Sun's web site today (see
http://java.sun.com/products/jdk/1.2/jre/).
Q: Will the Java Plug-in Software work with the next
release of the Java 2 SDK, Standard Edition?
A: Yes. With this release developers can configure the
Java Plug-in Software to use the Java runtime in the current
release of Java 2 SDK, Standard Edition v 1.2.2, enabling
developers to begin testing
their Java 2 SDK, Standard Edition v 1.2.2-based Java applets in
Navigator and Internet Explorer immediately.
Q: Is the Java Plug-in Software fully compliant with the
JCK (Java
Compatibility Kit) test suite for Java 2 SDK, Standard Edition v 1.2.2?
A: The 1.2.2 release of the Java Plug-in Software is
fully
compliant with the JCK test suite for Java 2 SDK, Standard Edition v
1.2.2, including the RMI and JNI tests.
Q: Netscape now provide enhanced JDK 1.1 support in
Communicator 4.X
-- is the Java Plug-in Software still necessary?
A: Yes. While Netscape has increased the number of JDK
1.1
features it supports in Communicator 4, it is still not feature
complete
nor fully compliant with the JCK. The Java Plug-in Software is the only
way to guarantee full support of the latest JDK and full JCK
compliance.
Q: Which Java 2 SDK, Standard Edition v 1.2.2 software
features does Netscape not support?
A: There are several, including support for multiple
JAR files
and not all thread methods are implemented. Netscape has provided
further
information on known incompatibilities in their JDK 1.1 patch for
Communicator
at http://developer.netscape.com/.
Q: Does Java Plug-in Software support signed applets?
A: Yes, Java Plug-in Software supports standard Java 2
SDK, Standard Edition v 1.2.2 signed
JARs. See Using
Signed Applets for more details.
Q: Does Java Plug-in Software support JNI?
A: Yes, Java Plug-in Software supports the Java Native
Method
Interface (JNI). See JNI
and Java Plug-in Software for more details.
Q: Does the Java Plug-in Software automatically recognize
and use
the proxy server configuration that the browser was using?
A: Yes, Java Plug-in Software automatically recognizes
the Internet
settings in your browser when it starts. It means that it can go over
the
firewalls/proxies as long as the settings in your browser are correct.
Q: What protocol does Java Plug-in Software support over
the proxy?
A: HTTP, HTTPS, FTP, and Gopher are supported in the
1.2.2 release of Java Plug-in Software.
Q: Does Java Plug-in Software support proxy-bypass list?
A: Yes, the 1.2.2 release of the Java Plug-in Software
supports the proxy-bypass list.
Q: Does Java Plug-in Software support
auto-proxy-configuration in
the browser?
A: Yes, the 1.2.2 release of the Java Plug-in Software
supports auto-proxy-configuration for both Internet Explorer and
Navigator.
Q: Does Java Plug-in Software support SSL?
A: The Java Plugin 1.2.2 provides HTTPS support but it
does
not provide direct SSL support.
JavaBeans Bridge for ActiveX Packager
back to top
Q: Can I use Java Plug-in Software to run Beans inside OLE
containers?
A: Yes, Java Plug-in Software includes the JavaBeans
Bridge for ActiveX. This
allows you to wrap your JavaBeans component as an ActiveX control and
deploy your Bean without any recoding inside applications like
Microsoft
Excel, Visual Basic, Inprise Delphi, etc.
Q: How does the JavaBeans Bridge for ActiveX inside Java
Plug-in Software work?
A: You run the Packager against the jar file containing
the JavaBeans
component(s). The Packager takes care of creating an OLE type library
and win32 registry for the component. This allows OLE/COM containers to
correctly analyze and present a JavaBeans component.
Q: What are the advantages of the Bridging functionality?
A: This provides users of legacy OLE/COM/ActiveX
containers such as Word
or Visual Basic with the ability to embed and use portable JavaBeans
components in the same way they would previously embed and use
platform-specific OLE/COM/ActiveX components. Component developers can
safely construct and deploy advanced, platform Java Plug-in Software
dependent JavaBeans
components with the knowledge that they will also be fully functional
inside of legacy applications.
Q: What does the Bridge allow JavaBeans components to do?
A: Beans can fire events that can be caught by
OLE/COM/ActiveX
containers. This allows, for example, a Bean to fire an event that is
caught by a Visual Basic script. Beans can act as servers for
OLE/COM/ActiveX method invocation. This means that tools such as Visual
Basic can invoke methods on Beans.
How Does it Work? back to top
Q: Does the Java Plug-in Software replace Microsoft's or
Netscape's
Java runtime with Sun's JRE?
A: No. The Java Plug-in Software does not replace the
browser's
underlying virtual machine. Rather, the Java Plug-in Software simply
enables
web page authors to specify that Sun's JRE is used instead of the
default
Java runtime.
Q: Do developers need to modify their applets in order to
support
the Java Plug-in Software?
A: No. Any Java 2 SDK, Standard Edition v 1.2.2-based,
100% Pure Java applets should run unmodified using the Java Plug-in
Software.
Q: What happens on browsers other than IE or Navigator, or
on non-supported
platforms?
A: The default conversion template provided with the
Java
Plug-in Software HTML Converter (used on the demonstration page), is
designed such that the applet will not be rendered in browsers other
than
Internet Explorer and Netscape Navigator on platforms other than
Windows 95,
Windows 98, Windows NT 4.0, and Solaris 2.5 and 2.6. However the Java
Plug-in Software HTML Converter provides
additional templates allowing web page authors to specify that on
non-supported platforms applets will be rendered using the original <APPLET>
tag using the browser's default Java
runtime. See this related question for more
information.
Q: As a web page author, how do I use the Java Plug-in
Software?
A: To utilize all of the features and capabilities of
Java 2 SDK, Standard Edition v 1.2.2 in IE or Navigator, web page
authors must modify the page's HTML
to specify the use of Sun's JRE via the Java Plug-in Software. Sun is
providing a written specification, to guide web page authors how to
make
these changes. In addition, Sun provides the Java Plug-in Software
HTML Converter, free of charge, that will automatically make the
changes
to the HTML of a selected web page (or set of web pages).
Q: How long does it take to download and install the Java
Plug-in Software
the first time?
A: The Java Plug-in Software installer is
approximately 5
MB in size. Download and install times will vary depending on the type
of network connection and overall system performance. We expect typical
total download and installation times (over a local area
network) will
vary from three to ten minutes. In subsequent encounters of web pages
that
specify the use of the Java Plug-in Software, it is invoked
instantaneously
from the user's hard drive and the applet is rendered.
Q: We are trying to deploy Java Plug-in Software within our
intranet environment. The Java Plug-in Software HTML Specification and
other online documents mention that
we should set up a Netscape Plug-in Software installation page within
our intranet for
Netscape users to install Java Plug-in Software. What does this page do
and how should
we set it up?
A: The purpose of this installation page is to act as
an entry point
for Netscape users to install Java Plug-in Software. If users encounter
an HTML page
that requires Java Plug-in Software, the user will get redirected to
this installation page according to the pluginspage attribute
in the EMBED tag.
At that point, the users should be able to download and install the
correct version of Java Plug-in Software for their platform. Thus, the
installation page
should have link to download the Java Plug-in Software binary.
An simple example page would look like:
<HTML>
<HEAD>
<TITLE>Java Plug-in Software Download Page</TITLE>
</HEAD>
<BODY>
<P><A HREF="ftp://myhost.com/public/jre12-win32.exe">
Java Plug-in Software Software 1.2.2 for Windows 95/98/NT</A></P<
<P><A HREF="ftp://myhost.com/public/plugin-12-solaris.bin">
Java Plug-in Software 1.2.2 for Solaris</A></P>
</BODY>
</HTML>
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Depending on how your webserver is configured, you may want to consider
using
CGI scripting instead of FTP for the download. Contact your webmaster
for more
information.
Q: Why is the download and installation experience
different in Netscape
Navigator than in Internet Explorer?
A: The releases of Netscape Navigator supported by the
Java Plug-in Software do not provide mechanisms that allow for the
automatic download
and installation of the Java Plug-in Software, as in Internet
Explorer. The first time Netscape Navigator comes across a web page
that
is enabled for the JavaPlug-in Software (the "activated page"), it
redirects
the user to another web page to download and install the Java Plug-in
Software software on the user's system. The user must then return to
the "activated
page" to render the applet using the Java Plug-in Software. From that
point forward, the browser automatically invokes the Java Plug-in
Software each time it comes across web pages that supports the
technology--completely transparent to the end user.
Q: How can I open the Java Plug-in Software Console on
Windows 95, Windows 98
or Windows NT?
A: On the Start menu, choose
Start-->Programs-->Java Plug-in Software Control Panel, then
select "Enable Console." After restarting the browser, you should see
the Console window.
HTML Converter back to top
Q: How will web page authors get the the Java Plug-in
Software HTML
Converter?
A: Sun is distributing the Java Plug-in Software HTML
Converter
royalty-free through the Java Plug-in Software HTML Converter download page.
Q: How do I install and run the HTML Converter 1.2?
A: In this release of the HTML Converter, there is
only one ZIP
file for downloading for all platforms (Win32, Mac, UNIX, Java). To
install the HTML Converter, unzip it using the appropriate
uncompression tool
(WinZip, unzip). To run the HTML Converter, do the following:
- change to the installed directory
- type java HTMLConverter
Notice that the HTML Converter 1.2 requires that JRE 1.2.2 be
installed.
Q: How significant or complex are the HTML changes required
to invoke
the Java Plug-in Software?
A: The Java Plug-in Software requires that web page
authors
make changes to their existing HTML code if they wish to have their
Java 2 SDK, Standard Edition v 1.2.2-based applets run using the Java
Plug-in Software, rather than the
browser's default Java runtime. While the changes are not trivial, they
are not overly
complex either.
To make this process easy for web page authors, Sun provides
the
Java Plug-in Software HTML Converter, free of charge, to automate this
process. In addition, Sun has provided a detailed specification
outlining
the HTML changes required to use the Java Plug-in Software, and how web
page authors can implement them "by hand". The Java Plug-in Software
HTML Converter can be downloaded from the HTML Converter download page.
For the HTML specification, see the Java Plug-in
Software HTML Specification.
Q: What capabilities do the supplementary templates
provided with
the Java Plug-in Software HTML Converter provide?
A: The Java Plug-in Software HTML Converter provides
both a default
template (default.tpl), and three supplementary templates. These
supplementary templates allow web page authors to more explicitly
target the browsers and platforms used in their environment when
modifying their pages using the Java Plug-in Software HTML Converter:
- default.tpl: The
default template used by the Java Plug-in Software HTML Converter. The
converted page can be used in Internet Explorer and Navigator to invoke
the Java Plug-in Software on the supported platforms.
- extend.tpl: The converted page can be used in
any browser
on any platform. If the browser is Internet Explorer or Navigator
on Windows 95, Windows NT, or Solaris, Java Plug-in Software will be
invoked.
Otherwise, the browser's default Java runtime is used.
- ieonly.tpl: The converted page can be used to
invoke Java Plug-in Software in Internet Explorer on the supported
platforms.
- nsonly.tpl: The converted page can be used to
invoke Java Plug-in Software in Navigator on the supported
platforms.
Q: How can I install the Java (.zip) version of the Java
Plug-in Software HTML Converter?
A: Set the CLASSPATH to the xxx.ZIP file that
you just downloaded, and type "java install".
Q: How can I run the Java (.zip) version of the Java
Plug-in Software HTML Converter after the installation?
A: The instructions are provided in the converter
directory.
Q. Why don't my signed applets work with Java Plug-in
Software?
A: Signed applets using the Java 2 SDK, Standard
Edition javakey mechanism are supported in Java Plug-in Software.
The most common problem is that the identitydb.obj
file is not in the expected home directory. To check where Java Plug-in
Software expects to find the user's home directory, you can use the
Java Control Panel to enable the Java Console. Then when Java Plug-in
Software starts up it will print out the user's home directory as the
third line on the console.
Make sure that your identitydb.obj file is in that
directory.
Q. The JIT doesn't seem to be enabled. Why not?
A: Normally the JIT is enabled by default. However
there is a known bug that can sometimes affect the JIT. To make sure
the JIT is enabled you can set the Windows environment variable JAVA_COMPILER=symcjit.
Troubleshooting back to top
Q: Why can I not get the control panel or the examples to
work with
Java Plug-in?
A: In order to use the control panel or the example
applets,
you must enable Javascript in your browser.
Q: I am having trouble using cookies with Netscape and Java
Plug-in 1.2.2,
but not with Internet Explorer. Why?
A: Because of a security fix for Java Plug-in 1.2.2,
in order for
cookies to be returned in Netscape 3/4, the URL must be based on the
applet's document root. The protocol, host, and file path (not
including the
filename) must be a subset of the URL that was requested. Please note
that the comparison between the applet document root and the URL is
case sensitive.
Q: Why does Java Plug-in sometimes crash Internet Explorer,
but not
Netscape Navigator?
A: In certain circumstances, bad HTML will cause the
browser to
crash. One example is the absence of an </XMP> tag. Please make
sure
your HTML is correct.
Q: Why does RSA signing not work in Internet Explorer 3.x?
A: RSA Applet signing is not supported in Internet
Explorer 3.02 due to
the limitation of the API implementation with this particular browser.
In order to have the RSA signing technology work, the plugin is
required to
have the Crypto 2.0 API installed and to be able to open and use the
Internet Explorer codestore to store, verify and retrieve certificates.
Unfortunately, Internet Explorer 3.0x does not not provide access to
its
codestore through the Crypto 2.0 API.
Q: My applet no longer works in Internet Explorer with Java
Plug-in 1.2.2.
Why?
A: With Java Plug-in 1.2.2 a new PARAM scriptable
tag was introduced. This tag must be included and given a value of
"true" in order for
an applet to be scriptable. See the HTML Specification for
more information.
Q: Why am I having problems using some standard extensions?
A: In Java Plug-in 1.2.2, only extensions installed in
the
<jre>\lib\ext directory will be added to the classpath.
Extensions
installed in directories pointed to by the java.ext.dirs system
property
will not be added.
Q: I cannot unzip the HTML Converter zip file. Why not?
A: This file is actually a jar file. To uncompress the
file type jar -xvf zip file at the command line.
If you want to use a
compression program, we recommend the latest version of WinZip.
Q: Java Plug-in 1.2 .2 Software used to work with my
Navigator 4.0.x browser. But
when I upgraded to Navigator 4.5 and re-installed Java Plug-in Software
1.2.2, Java Plug-in Software does not work with Navigator 4.5. Why?
A: It has been reported that Navigator 4.5 may not
install the user
profile properly during installation. As a result, Java Plug-in
Software may not read
the correct user profile setting. To make sure the user profile setting
is
correct, please check the following:
- HKEY_LOCAL_MACHINE\Software\Netscape\Netscape
Navigator\Users\CurrentUser
- HKEY_LOCAL_MACHINE\Software\Netscape\Netscape
Navigator\Users\<UserName>\DirRoot
Please make sure that these two registry keys exist and the
<DirRoot>
points to an existing user profile. If any of the registry keys are
missing or incomplete, please use the User Profile Manager tool to
recreate your profile.
Q: It has been reported that Java Plug-in 1.1.x
Software does not work well
with Navigator 4.5 because of a system resource conflict. Is this
problem resolved in Java Plug-in 1.2.2 Software?
A: Yes. The system resource conflict has been resolved
in Java 2 SDK, Standard Edition/JRE v 1.2.2
which includes Java Plug-in 1.2.2 Software.
Q: My Swing applet used to work in Java Plug-in 1.1.x
Software. After I
upgraded to Java Plug-in Software 1.2.2, it doesn't work any more. Why?
A: Java Plug-in 1.1.1 Software includes Swing 1.0.3,
which supports the package
name com.sun.swing.*. Now Java Plug-in 1.2.2 Software
includes Swing 1.1 which supports the new package javax.swing.*.
As a result, any attempt to
run the old Swing applet in Java Plug-in 1.2.2 Software will result in java.lang.NoClassDefFoundError.
This problem can be resolved by migrating your Swing applet to the new javax.swing
package name.
Q: We are trying to use Java 3D with Java Plug-in Software,
but it doesn't work
at all. Why?
A: Java 3D comes with various packages. Installing it
incorrectly may
inadvertently disable Java Plug-in Software or cause it to fail. Follow
these general instructions for using Java 3D and Java Plug-in Software:
- Install Java Plug-in Software first.
- Install Java 3D in a new directory. Do not install it over
the existing
Jva 2 SDK, Standard Edition/JRE. See this page for
installation instructions.
- In the Java Plug-in Software control panel, switch the JRE
to the one that came with
Java 3D.
- Download the HTML Converter 1.2 and convert the Java 3D
demo pages.
The Java 3D demos should now run within Java Plug-in Software.
Q: Some web/proxy server require users to login for
authentication. When
I used the browser to access this server with Java Plug-in Software,
two login dialog boxes appeared. Why?
A: Normally Java Plug-in Software will download the
applet or Bean using its
own connection. If the web/proxy server requires a login, the browser
will
first encounter the request and bring up a login dialog box. After the
HTML
page is downloaded, Java Plug-in Software will try to download the
class or jar files for
the applet. However, since Java Plug-in Software has no access to the
login information
that the browser previously obtained, it will bring up its own login
dialog box.
Q: My signed applet is working fine in Java 2 SDK, Standard
Edition/JRE AppletViewer. However, after I start using Java Plug-in
Software in Internet Explorer or Netscape Navigator, it stops working.
What's going on?
A: AppletViewer and Java Plug-in Software look for the
identitydb.obj file in different locations. Please make
sure the identitydb.obj file is in the right location when
running Java Plug-in Software. For more details, please check http://java.sun.com/products/plugin/1.2/docs/index.docs.html.
In other cases, the applet fails in Java Plug-in because Java
Plug-in runs applets in untrusted mode. To test this properly in
AppletViewer, always specify an
http URL if possible. If this is not possible, make sure the applet
classes are not in your CLASSPATH and use a file URL.
Q: When I tried to deploy Java Plug-in Software in the
intranet and put the
binaries in the internal web server, IE doesn't download and install
Java Plug-in Software when it encounters the converted page. What's
going on?
A: You may want to check that the CODEBASE
in the OBJECT tag actually has the correct URL for the Java
Plug-in Software. Also, turning off execute privileges on the directory
in which you put the Java Plug-in Software executable may help.
Q: I am trying to install the Java Plug-in Software in a
network drive. However, it doesn't install. Why?
A: If your network drive is protected or read-only,
you will not be able to install the Java Plug-in Software. Please
contact your system administrator for more details.
Q: In Java Plug-in 1.1.x Software, there was an
option called "Network
Access" in the Java Plug-in Software control panel. In Java Plug-in
1.2.2 Software, this option seems to be disabled. Why?
A: Java Plug-in 1.2.2 Software comes with Java 2 SDK,
Standard Edition/JRE 1.2.2, which does not support
the "Network Access" option. To allow applets to connect to other
hosts, use signed applets or change the policy file. See the Java 2 SDK, Standard Edition v 1.2.2
documentation for more information.
Since Java Plug-in 1.2.2 Software still supports JDK/JRE 1.1.x,
this option can be
enabled if users select JDK/JRE 1.1.x to use with Java Plug-in
1.2.2 Software from
the control panel.
Q: I am trying to install Java Plug-in Software. However,
whenever the install program tries to install the Java Plug-in Software
for Netscape Navigator, it displays an error. My Navigator is on a
network drive. Is there a way to fix this?
A: If your Navigator is installed on a network drive,
you may not have the permission to install the plugin DLL into the
Navigator Plugins directory. Please contact your system administrator
for more details.
Q: I'm having trouble installing the Java Plug-in Software
on my Win32
machine. I see the error: "An application error has occurred and an
application error log is being generated. Exception: access violation
..."
What might be the problem?
A: The Win32 installation (using Installshield's
installer)
may not work if you have Quarterdeck's Cleansweep product running in
the background.
Q: I am experiencing problems getting an applet to render
using Java Plug-in Software. What is the cause of this?
A: While this may be due to a variety of circumstances
unique to your operating environment, two frequent causes of this
problem and the requisite workarounds are provided below:
Scenario 1: Security Exception
I am using the Java Plug-in Software and each time I try to load an
applet on a web page that specifies the Java Plug-in Software, when the
applet is loaded, a SecurityException is triggered.
Problem:
Your network does not support DNS (Domain Name Service).
In order to perform certain security checks, the Applet SecurityManager
needs
to be able to find the IP address from which your applet was
downloaded.
If DNS is not available, these security checks may fail.
Workaround:
When visiting the target web page, specify an IP address rather than a
hostname in the URL. For example, use "http://123.45.35.128/fred.html".
Scenario 2: Applet does not start using IE 3.02 and NT 4.0
I am using the Java Plug-in Software to run the demos on Sun's web
site,
using Internet Explorer 3.02 on Windows NT 4.0. Instead of rendering
the applet, the browser displays a message that says "Your browser
understands
the <APPLET> tag but is not running the applet for some
reason"
Problem:
This is caused by an installation bug in Internet Explorer
3.02. When you install Internet Explorer 3.02 on Windows NT 4.0, some
of
the settings are stored in the HKEY_CURRENT_USER in the Windows
registry.
However, when you login to Windows NT using another user account, these
settings in the registry can no longer be accessed because they are in
a different user account.
Workaround:
Either reinstall Internet Explorer 3.02 in the current
user account, or install Internet Explorer 4.
Q: I changed my browser setting when Java Plug-in Software is
running,
but it still uses the old settings after the change?
A: The browser settings are read in by Java Plug-in
Software when it is started. These settings are valid throughout the
lifetime of
the browser session. To make Java Plug-in Software read in the new
settings,
simply restart your browser. If you running Active Desktop
with Java Plug-in Software, you need to restart the machine.
Q: Using Navigator, when I print a web page that contains
an applet using Java Plug-in Software, the applet does not show up in
the printout. Why?
A: This is caused by a bug in the Java Plug-in
Software API in Navigator 4.0 and
later. There is currently no workaround to this problem. This problem
does not
appear when using Java Plug-in Software with Navigator 3.0.
Q: When I loaded my applet, it said "noninit" or "applet
not initialized" in the browser's status bar. How can I identify the
cause of the problem?
A: Follow these steps:
- Select Java Console from the Java Plug-in Software Control
Panel and
run
the applet again.
- Look at the error message in the Java Console.
- If you are accessing the applet through the network, make
sure the
proxy
info shown in the Java Console is correct.
- Make sure all the class/JAR files are in the right
directory.
- Make sure the converted HTML page is correct.
- Try the unconverted page with AppletViewer on the same
machine. If it
works,
please recheck 3, 4, and 5 again.
Q: After I install Java Plug-in Software, why won't the
Win32 Java Plugin Software load in Navigator?
A: It may be that installation of Java Plug-in
Software didn't complete
successfully. Make sure the file NPJava32.dll is in the
Plugin directory. Otherwise, just copy it from the PlugJava Plugin
Software/bin directory, and it should
work.
Q: When using Java Plug-in 1.2.2 Software or the HTML
Converter 1.2 on a Japanese
version of Windows98, the system is unstable. Is there a solution?
A: This problem is caused by bugs in the Input Method
Editor (IME)
that comes with Windows98. Install the Input Method Editor Service
Release 1
(IME-SR1) for Windows98 from Microsoft before running Java Plug-in
1.2.2 Software or the HTML Converter 1.2.
Q: When I try to use the AppletClassLoader with Java
Plug-in 1.2.2 Software, it
crashes with a null pointer exception in IE4, but works fine in
Netscape.
Why does this happen? Is there a way to make it work correctly in IE4?
A: Java Plug-in 1.2.2 Software in IE4 tries to load
<YourAppletName>BeanInfo.class even if your applet is not
a bean. There is a bug in Java 2 SDK, Standard Edition v 1.2.2 in
the AppletClassLoader that occurs when trying to load nonexistent
classes. To prevent
this problem, create an empty <YourAppletName>BeanInfo.class.
Miscellaneous Questions back to top
Q: How can I tell what version of Java Plug-in Software has
been installed?
A: There are a couple of ways:
- Check the version number in C:\Windows\Downloaded
Program Files\Java Runtime Environment. If the version number is
1,2,0,0, it is Java Plug-in Software Software
1.2. Otherwise, it is Java Plug-in 1.1x Software.
- Open Netscape Navigator. Go to the Help->About Plugins
menu. Check all
the MIME types in NPJava11.dll and NPJava32.dll. If the following
exist:
- "application/x-java-applet;version=1.2", you are using
Java Plug-in 1.2 Software
- "application/x-java-applet;version=1.1.2", you are
using Java Plug-in 1.1.2 Software
- "application/x-java-applet;version=1.1.1", you are
using Java Plug-in 1.1.1 Software
- "application/x-java-applet;version=1.1", you are using
Java Plug-in 1.1
Software
Q: I have Java 2 SDK, Standard Edition v 1.2 beta 4, RC1,
RC2, and FCS releases on my system. How do I know which Java 2 SDK and
Java Plug-in Software I am using?
A: We strongly recommend that users uninstall all Java
2 SDK, Standard Edition 1.2 beta 4,
RC1, or RC2 releases from all systems and install the Java 2 SDK,
Standard Edition 1.2.2 FCS release
instead. This will insure that you have the latest version of the JDK
and
Java Plug-in Software.
Q: Is there a way to pre-load Java Plug-in Software during
the browser startup?
A: Internet Explorer and Netscape Navigator do not
have mechanisms
to support pre-loading Java Plug-in Software during startup. You can
work around this
limitation by providing your own startup page that launches a dummy
applet
using Java Plug-in Software.
Q: How do I specify a JAR file as part of an OBJECT
or EMBED tag?
A: You can specify one or more JAR files by defining
an ARCHIVE
parameter to the OBJECT or EMBED tag.
With the OBJECT tag this looks like:
<PARAM
NAME=archive VALUE=demo.jar,fred.jar>
With the EMBED tag this looks like:
archive=demo.jar,fred.jar
Q: Does Java Plug-in Software support multiple JAR files in
the ARCHIVE attribute in the APPLET tag? If so,
why can't
I get this to work?
A: Java Plug-in Software supports the ARCHIVE
attribute
in both the EMBED and OBJECT tags. The most common
mistake
is to put the JAR files in the wrong order. For example, if you use the
Swing
set in Java Plug-in Software and specify ARCHIVE="Myjar.jar,swing.jar,..."
Java Plug-in Software will fail to load the applet because by the time Myjar.jar
is loaded and Java Plug-in Software tries to
initialize
the applet, swing.jar is not yet loaded. The JAR files in the
ARCHIVE should be in the order of dependency. Since Myjar.jar
depends on everything else, it should be put at the end of the list.
The
other common mistake is to put spaces or paths with the JAR file lists.
Q: Does Java Plug-in Software support Drag and Drop between
applets and the native environment? If so, why can't I get it to work?
A: Yes, Java Plug-in Software does support Drag and
Drop. You must make sure
to grant the applet the correct socket permissions using policytool
to use this feature. Please see the SocketPermission class
documentation for more information.
Q: What is the applet lifecycle in Java Plug-in Software?
Is it different than in 1.1?
A: The applet lifecycle in Java Plug-in 1.2.2 Software
is the same as it was
in 1.1. When an applet is encountered on an HTML page, the applet will
be
initialized and started. When the HTML page is closed, or the back
button is pushed, the applet with be stopped and destroyed immediately.
When the same HTML page is encountered again, the applet will
be initialized
and started again.
Q: My applet used to create a top level frame that would
remain visible
through page switches. When I upgraded to Java Plug-in 1.2.2 Software
this no longer
occurs. Why?
A: In Java Plug-in Software Plugin Software, applets
are stopped and destroyed during page
switches. All the visible components should be destroyed as well. There
has
been an enhancement in Java 2 SDK, Standard Edition/JRE 1.2.2 that
makes sure that all of the resources of
the applet are properly released, including the top level frame.
Q: When I uninstall Java Plug-in Software, the Win32 plugin
seems
to stay in the machine. How can I remove that?
A: Delete the NPJava32.dll from the Plugin
directory.
Q: Why do I get a yellow banner across my applet frame when
using
Java Plug-in Software?
A: When an applet creates a free-standing Frame, Java
Plug-in Software adds a yellow warning banner so users will realize
they are dealing
with an untrusted applet window.
Q: Can I disable the yellow warning banner on frames?
A: The yellow warning banner is an important security
feature.
It cannot be disabled by untrusted applets.
If you use a signed applet, where the signing key is trusted
by the
end user, then the warning banner will not be shown.
Q: How do I prevent the warning banner covering my GUI
state?
A: You should use the getInsets() method to
find
the size of your frame's decorative border. This includes the warning
banner. For example, if you create a Frame with size 100x100,
you
might find it has insets [top=42,left=5,bottom=5,right=6]
giving
you a drawable area of 89x53. You need to position your work within
the drawable area.
If you need to create a drawable area of a particular size,
first create and show the Frame, then use getInsets
to find the insets' sizes, then figure out the desired frame size by
adding your desired size to the insets, then use frame.setSize()
to set your frame to that size.
Q: Why does InetAddress.getLocalHost().getHostName() return
"localhost"?
A:
This is a deliberate security feature in the Java 2 platform. Untrusted
applets
will not be given the real host name.
Trusted applets (such as signed applets) will be given the
real host name.
Q: Are the MIME types "application/x-java-vm/java-applet"
and
"application/x-java-vm/java-bean" still recognized by Java Plug-in
Software?
A: These two MIME types were used by the Java Plug-in
Software EA1 release. In EA2, we introduced four new MIME types:
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"application/x-java-applet" |
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"application/x-java-applet;version=1.1" |
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"application/x-java-bean" |
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"application/x-java-bean;version=1.1" |
Java Plug-in 1.2 Software supports the following MIME types:
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"application/x-java-applet;version1.2" |
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"application/x-java-bean;version=1.2" |
For more information about these MIME types, please check the
Java Plug-in Software
HTML Specification. The old MIME types were still supported in EA2 and
EA3 for
backward compatibility. However, these two old MIME types are not
supported
in the FCS release. Please update your HTML pages accordingly.
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