“The Java 7u21 release introduces changes to security messages related to running Java applets and applications,” Oracle said in a technical document that explains the changes.

In April, Oracle instituted a number of changes starting with Java 7u21. The new update introduced prompts warning users that an unsigned applet could potentially harm the user’s computer.

Description: Multiple vulnerabilities existed in Java 1.6.0_51, the most serious of which may allow an untrusted Java applet to execute arbitrary code outside the Java sandbox.