B Configuring Java Plug-ins

This section describes the use of Sun Java Plug-in as a Web browser plug-in. Sun Java Plug-in enables users to run Oracle Forms applications using Mozilla Firefox or Internet Explorer. It provides the ability to specify the use of a specific Java Virtual Machine (JVM) on the client. For more information, see the white paper "Using Sun's Java Plug-in" at http://www.oracle.com/technology/products/forms/index.html.

B.1 Supported Configurations

Oracle supports the Sun Java Plug-in. For more information, see the Java Plug-in Documentation at http://java.sun.com/products/plugin/reference/docs/index.html.

B.2 Legacy Lifecycle Behavior And Configuration Requirements

In JDK 1.4.1 and later, the Sun Java Plug-in supports the LEGACY_LIFECYCLE applet parameter. When this parameter is set to true, a running applet is not destroyed when the user navigates away from a page. Furthermore, when the user navigates back to the page, the running applet is resumed unless:

The browser must re-issue the request for the applet definition, and
The response to that request produces an applet definition that differs from the applet definition that was returned by the original request.

B.2.1 Configuration Requirements

To use the LEGACY_LIFECYCLE feature for certain configurations, add LEGACY_LIFECYCLE=true parameter to the relevant configuration sections, such as in formsweb.cfg.

Alternatively, legacy_lifecycle=true can be specified on the URL that is used to launch a Forms application. This technique is useful primarily during application development.

In addition, JavaScript must be enabled in the browser from which the Forms application (that specifies legacy_lifecycle=true) is launched.

The HTML files must also adhere to certain guidelines. The base HTML files that are shipped with the product already adhere to the required guidelines. However, users who write their own base HTML files must ensure that such files adhere to the following guidelines:

The base HTML file must define the serverURL attribute to the value of the serverURL variable (serverURL="%serverURL%"), in the COMMENT node that has the ID forms_plugin_info.
The base HTML file must define the serverURL applet parameter, and its value must be the value of the appletServerURL variable. (Prior to Forms 11g, it was set to the value of the serverURL variable). This can be accomplished by including

<PARAM NAME="serverURL" VALUE="%appletServerURL%">

and

serverURL="%appletServerURL%"

in the OBJECT definition and the EMBED comment in user-written base HTML files. Note that the appletServerURL variable should not be set in a configuration file. (If it is, the value is ignored.) Instead, Forms computes its value automatically: if legacy_lifecycle=true (in the configuration file or in the initial URL), then the appletServerURL variable evaluates to "?", which causes Forms to look for the serverURL attribute of the COMMENT node (see above). Otherwise, the appletServerURL evaluates to the value of the serverURL variable.
The base HTML file must define the legacy_lifecycle applet parameter, and the value must not be hard-coded: it must match the value of the legacy_lifecycle variable. That is because in Forms 11g, the variable also affects the value of the appletServerURL variable (as explained above). This can be accomplished by including

<PARAM NAME="legacy_lifecycle" VALUE="%legacy_lifecycle%">

and

legacy_lifecycle="%legacy_lifecycle%"

in the OBJECT definition and the EMBED comment in user-written base HTML files.