question: public void putAllWithPrefix ( TungstenProperties props , String prefix ) { TungstenProperties newProps = new TungstenProperties ( ) ; if ( props . isEmpty ( ) ) { newProps . setObject ( prefix , props ) ; } else { for ( String key : props . keyNames ( ) ) { newProps . setObject ( prefix + key , props . getObject ( key ) ) ; } } putAll ( newProps ) ; }
target:  Prefixes all the given properties with the given string and merges this new set with the actual ones, overriding current values with same keys if any