public void enforceMaxLength(int maxLength) {
    if (getCharacterLength()!=maxLength)
      set(getHiveChar(), maxLength);
  }
HiveCharWritable.
String values will be padded to full char length.
Character length, comparison, hashCode should ignore trailing spaces.
serde/src/java/org/apache/hadoop/hive/serde2/io/HiveCharWritable.java