Security warning when running JViews application with applet on Microsoft Windows operating system

Question

Why do I get the security warning when running JViews application with applet on Microsoft Windows operating system?

Answer

JViews JAR files are signed. Additionally, it provides various external JAR files from different providers that are unsigned. Starting with Java 6 Update 19, Oracle introduced a specific security check into Java concerning the mix of signed and unsigned code. As consequence, you might see the following warning dialog on Microsoft Windows operating systems when starting an applet or Java Webstart application:

The JViews jars are safe, hence you should answer "No" in this dialog, to avoid the JViews applets from being blocked. You can disable the dialog globally by starting the Java Control panel (accessible from the Microsoft Windows Control panel) and disable all mixed code security verification, as illustrated in the following picture:

Another possibility to avoid this dialog box is to unsign all JAR files (by extracting each JAR file and recreating it with a new manifest), or to pack your entire application into one big JAR file containing all required JViews classes, and signing this JAR file with your own certificate.