The new plugin supports runngin java applets in 1.4.2 and 1.5 JVM. Deploy and plugin code on client vm side need be compatible with as low as 1.4.2. The current animation panel is using some jre 6 feature. It throw ClassNotFound, for example, java.awt.RadialGradientPaint.class, when run in 1.5.x jvm.
To support multiple JREs, Animation Panel need take jre runtime version into consideration.
The AnimationPanel already contained commented-out alternatives for
most of the uses of Java 6 specific APIs. Added run-time detection of
the JRE version in use (avoiding external dependencies as much as
possible) and use of these alternate code paths. Disabled the glow
around the progress bar when not running on Java 6 since that did not
seem easy to backport and is a relatively small visual difference.