question: public static void prepareDotProject ( File projectSourceFolder ) { File dotProject = new File ( projectSourceFolder , ".project" ) ; File dotProjectTemplate = new File ( projectSourceFolder , "_project" ) ; if ( dotProject . exists ( ) ) { if ( ! dotProjectTemplate . exists ( ) ) { throw new IllegalArgumentException ( "proband must rename the '.project' file to '_project'" ) ; } } if ( dotProjectTemplate . exists ( ) ) { try { Files . copy ( dotProjectTemplate . toPath ( ) , dotProject . toPath ( ) , StandardCopyOption . REPLACE_EXISTING ) ; } catch ( IOException e ) { throw new IllegalStateException ( "unable to prepare .project-file" , e ) ; } dotProject . deleteOnExit ( ) ; } }
target:  For Test-mocks copies over "_project"-files to ".project" files and supplies a delete-on-exit shutdown hook for them.