Which syntax is appropriate for concatenating variables in VTL?

The appropriate syntax for concatenating variables in VTL (Velocity Template Language) is represented by using the format that includes variables within curly braces directly adjacent to each other. In this case, the combination of ${firstName}${lastName} effectively concatenates the two variables together without any spaces or separators. This approach allows both variables to be processed as a single string output, resulting in the full name being displayed as one continuous sequence of characters.

Using the curly braces ensures that the Velocity engine interprets each variable correctly, retrieving their values before concatenation. This syntax is advantageous when you want to create a cohesive string from multiple values.

In contrast, other options do not facilitate concatenation in the same manner. For instance, variable expressions like $identityName and $!identityStatus do not implement concatenation; rather, they reference individual variables or their values outright without combining them into a single output.