Users just want to to be able to add placeholders to the values of configuration (not the keys). The mechanisms for resolving the placeholders hereby should be not constraint to one single lanmguage like EL. Instead of different replacement strategies should be selectable, e.g. by prefixing an expression with the name of the resolver that should do the work (eg "blabla ${env:HOME} using Java version ${sys:java.version}.". This allows resolution mechanism to be isolated easily and also allows to use simpler mechanisms, if no more complex ones like EL are required. This is especially useful to deal with low resource environment like ME.