I accidently stumbled over the problem that I could not use Java classes packaged in namespace 'as'. Example (Java-Code with embedded Groovy-script): import as.AsTest; public class TestAs { // different trials: private static String groovyCode1 = "import as.AsTest as a; " + "return new AsTest(); "; private static String groovyCode2 = "import as.*; " + "return new AsTest(); "; private static String groovyCode3 = "return new as.AsTest(); "; private static String groovyCode4 = "import as.AsTest; " + "return new AsTest(); "; public static void main(String[] args) { AsTest a = new AsTest(); // Ok GroovyShell shell = new GroovyShell(new Binding()); Object value = shell.evaluate(groovyCode3); // ..1-4 System.out.println(value); return; } } Error message is 'MultipleCompilationErrorsException'. 'as' is a reserved word in Groovy. Nevertheless I think 'as' should be allowed as namespace-name (as it is allowed in Java).