Java Jnlp CodeSigner Error

I am trying to run a java jnlp application from my computer. Every time I try launch the file I get the error java.lang.NoClassDefFoundError: java/security/CodeSigner

From searching Google it seems to be a common enough problem and is normally blamed on 'java 6'. I couldn't find a solution that doesn't involve rolling back to an older java version.

Doe开发者_运维知识库s anyone know how fix this without reverting versions?

Looks like SUN JRE 1.6.0_14 was the last SUN JVM without that nasty bug... I'd install that version in parallel and use it more or less exclusively for jnlp applications, that still request Java 1.4. (guess you can't change the jnlp application so that it request a higher Java version)