1. Values which are expanded statically during parsing 2. Values which are fully dynamic - i.e. lookup is performed everytime you access the value (so if you change the original, the dependent changes as well).

I use something in between the two. When a property is fetched, expand any ${inline.properties} or %ENVVARS% before returning the value. This is more flexible than 1, as you can refer to properties before they've been defined: product.home = ${common.home}\product ... common.home = c:\foo\bar

2. Values which are fully dynamic

Is that really a common requirement? Every time I need inline value expansion it's usually to do with file system paths, and they're usually values that will never change once the software's been installed, let alone dynamically at runtime. Trent.