public void toLowerCase() {
    for (int i = 0; i < nodes.length; i++) {
      nodes[i] = nodes[i].toLowerCase();
    }
    if (fullPath != null) {
      fullPath = fullPath.toLowerCase();
    }
  }
String basic total, 32B

<ul>
  <li>Object header, 8B
  <li>char[] reference + header + length, 8 + 4 + 8= 20B
  <li>hash code, 4B
</ul>
iotdb-core/node-commons/src/main/java/org/apache/iotdb/commons/path/PartialPath.java