{#Constants.COMPLETE_NAME} allows to use {##expr} to replace the value of the Java expression expr within attribute values and text nodes.

For expression interpolation in text nodes the difference is to the usual xsp:expr syntax is minor. For dynamic attribute values, however, interpolation keeps it much more concise and readable.

        
          String world = "world";
          String color = "red";
        
        ]]>
      

Just compare this:

Hello simple {#world}!]]>
      

to that:

color:colorHello complex world!]]>
      

Interpolation can also be used in logicsheets: