private static Token internToken(Token t) {
    if (t == null) {
      return null;
    }
    if (t instanceof ImmutableCommonToken) {
      return TOKEN_CACHE.intern((ImmutableCommonToken) t);
    } else {
      t.setText(StringInternUtils.internIfNotNull(t.getText()));
      return t;
    }
  }
Tag this ASTNode with information about the object from which this node
originated.
parser/src/java/org/apache/hadoop/hive/ql/parse/ASTNode.java