private static long getMinValue(final PrimitiveType type, String typeName, long defaultValue) {
    if(isUnsignedInteger(type)) {
      return 0;
    } else {
      switch (typeName) {
      case serdeConstants.INT_TYPE_NAME:
        return Integer.MIN_VALUE;
      case serdeConstants.SMALLINT_TYPE_NAME:
        return Short.MIN_VALUE;
      case serdeConstants.TINYINT_TYPE_NAME:
        return Byte.MIN_VALUE;
      default:
        return defaultValue;
      }
    }
  }
ETypeConverter is an easy way to set the converter for the right type.
ql/src/java/org/apache/hadoop/hive/ql/io/parquet/convert/ETypeConverter.java