Java 7 and Java 8 have, by default, restricted the use of creating Java objects within XSL since it can allow access to the JVM from the XSL file. One valid use case for it, however might be to use Java date objects like this:
<xsl:variable name="nowDate" select="java:java.util.Date.new()"/>
There are two options I would recommend:
1. XSL 2.0 has built in date functions, which can be used instead of using Java date objects. http://www.w3.org/TR/xslt20/#format-date
2. If you want to still use Java objects in your XSL, in the QIE Service Manager, add the following line to your Startup tab, Arguments section:
-Dqie.allowXslInsecureProcessing=true