Fail to compile when there is a method return List<int[]>

For a simple class with a method that return a List<int[]>, i.e.
class Tester{
List<int[]> getList()

{ return [[0,0] as int[]]; }

}

It cannot compile. the following are error message:
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: illegal start of type
public java.util.List<[I> getList()

{ return (java.util.List<[I>)null;}
^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: ';' expected
public java.util.List<[I> getList() { return (java.util.List<[I>)null;}

^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: invalid method declaration; return type required
public java.util.List<[I> getList()

{ return (java.util.List<[I>)null;}
^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: illegal start of expression
public java.util.List<[I> getList() { return (java.util.List<[I>)null;}

^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: ';' expected
public java.util.List<[I> getList()

{ return (java.util.List<[I>)null;}
^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: illegal start of expression
public java.util.List<[I> getList() { return (java.util.List<[I>)null;}

^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: ';' expected
public java.util.List<[I> getList()

{ return (java.util.List<[I>)null;}
^
C:\Documents and Settings\USERNAME\.grails\1.0.2\projects\test_grails\generated-java-source\Tester.java:13: not a statement
public java.util.List<[I> getList() { return (java.util.List<[I>)null;}

^
8 errors
Compilation error: Compile failed; see the compiler error output for details.

Notice that it's a Grails application and the compilation is done when i run grails run-app. It seems there is no problem when use IDEA to do unit test against the method.