ä ö ü 
Ä Ö Ü 
ß ß ß 
+ + + 

This page should display a set of german umlauts and plus signs.
The encoding is set on the JSP using the in the <%@ page pageEncoding="UTF-8" %> JSP directive, and also in the "content-encoding" property of the file, which is also set to "UTF-8".

Note: This page actually might display garbage characters, depending on your default encoding setting. This does not affect the usability of JSP in general, in case you require UTF-8 encoding with your JSPs you should set the default encoding of the OpenCms installation to "UTF-8" in the opencms.properties.