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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:
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://bugreport.sun.com/bugreport/index.jsp
A: When reporting bugs against Java Plug-in Software, always include the following information:
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:
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:
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
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:
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:
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:
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?
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
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:
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:
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.
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://184.108.40.206/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"Q: I changed my browser setting when Java Plug-in Software is running, but it still uses the old settings after the change?
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.
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:
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:
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> </listing> With the EMBED tag this looks like: <listing> archive=demo.jar,fred.jar </listing> 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: <table> <tbody> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-applet"</td> </tr> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-applet;version=1.1"</td> </tr> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-bean"</td> </tr> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-bean;version=1.1"</td> </tr> </tbody> </table> Java Plug-in 1.2 Software supports the following MIME types: <table> <tbody> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-applet;version1.2"</td> </tr> <tr> <td> </td> <td> </td> <td> </td> <td>"application/x-java-bean;version=1.2"</td> </tr> </tbody> </table> 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. 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