public static void isLegalNamespaceName(byte[] namespaceName) {
    isLegalNamespaceName(namespaceName, 0, namespaceName.length);
  }
Qualifier names can only contain 'word' characters <code>[\p{IsAlphabetic}\p{Digit}]</code> or
'_', '.' or '-'. The name may not start with '.' or '-'.
@param qualifierName byte array containing the qualifier name
@param start         start index
@param end           end index (exclusive)
hbase-common/src/main/java/org/apache/hadoop/hbase/TableName.java