The format of the cache is completely changed and should never be assumed. Any existing code using the previous cache format for Java Web Start or Java Plug-in will no longer work. Existing applications in the Java Web Start cache will be upgraded and converted to the new cache format the first time you run a Java Web Start application, or if you launch the cache viewer using javaws -viewer.
The system cache will be upgraded and converted to the new format the first time you launch Java Web Start in system mode, or if you just launch javaws -system.
The caching mechanism and download engine are redesigned and consolidated between Java Web Start and Java Plug-in. This brings several new features to Java Web Start, previously available only in Java Plug-in and vice versa. They are :
<no-cache> directive is now supported. When the no-cache directive is used , an update check is made to make sure the cached contents are same as at the URL. The resource is then downloaded into the cache and the expiration field is ignored. In Java SE 6 unsigned Java Web Start applications that specify a version other than the latest one will trigger a security warning, requiring explicit user permission before the application will run. Signed Java Web Start applications are not affected.
Java Web Start and Java Plug-in now support CRL (Certificate Revocation Lists) and OCSP (Online Certificate Status Protocol) for verifying the certificates.
Java Control Panel provides an option to select the default SSL handshaking protocol. The default is set to SSLv3 and SSLv2. You can also change it to TSL.
The Java Console is excluded from modality. By using the new modality features of AWT in Java 6, you can interact with Java Console even when your application is displaying a modal dialog.
All dialogs and screens of Java Web Start and Java Plug-in are redesigned to be more user friendly, intuitive, and accessible.