Normally Groovy Server Pages (GSP) are compiled to class files when we create a WAR file of our application. If we want to compile the GSP without creating a WAR file we use the command-line argument ---gsp. Grails will compile the source code of our application and also the Groovy Server Pages. This way we can detect for examples faulty import statements in the GSP source code.

$ grails compile ---gsp 
...
| Compiling 12 GSP files for package [sampleGrails]
...