How do I add a customised popup for a Java RCP application which launches only when it has java 7 or higher versions(32-bit)?

Currently, I have an application which is built using Java RCP(Eclipse Mars). It can launch only if the system has JAVA 7 Or any other higher version(32-bit only). When trying to launch using JAVA 6 it throws up a popup.(See attached popup).[Some Users might still have Java 6 in their system]. I would like to add my own customised dialog instead of this. How can this be achieved? Any thoughts? I'm attaching the error log here for your reference.Error Log