diff --git a/src/main/antlr4/astRefactor/astRefactor.g4 b/src/main/antlr4/astRefactor/astRefactor.g4
index 93b89ef4..8e376338 100644
--- a/src/main/antlr4/astRefactor/astRefactor.g4
+++ b/src/main/antlr4/astRefactor/astRefactor.g4
@@ -101,7 +101,7 @@ ACCESSMODIFIER      : ('public' | 'private');
 WHITESPACE          : ' ';
 NEWLINE             : ('\r'? '\n' | '\r')+ ;
 GENERICDECLLIST     : 'List<T>';
-SOURCEFILE          : (UPPERCASE | LOWERCASE)+'.java';
+SOURCEFILE          : WORD '.java';
 ASSIGNTOFIELD       : 'assigntofield';
 ASSIGNLEFTSIDE      : 'assignleftside';
 WHILESTMT           : 'while()';