I think this gets the result you need:
boolean[] getKeyUsage( int mask ) {
(7..0).collect { int it ->
( ( mask >> it ) & 1 )
}
}
getKeyUsage( 144 ) == [ true, false, false, true, false, false, false, false ]
The error you were getting is because you construct arrays in Groovy with:
byte[] bytes = [ 1, 2 ]
Not the new byte[] { 1, 2 }
Java way. But I don't believe you need the byte array...