The classes in org.apache.parquet.column.values.boundedint aren't used. It looks like this was intended to be the "right" way to use the RLE/BitPacking hybrid, but callers ended up instantiating the RLE encoder or writer directly.
The ZeroIntegerValuesReader and DevNullValuesWriter are used, but should be relocated. The ZeroIntegerValuesReader is only used when the encoding is RLE (in Encoding.java) and the DevNullValuesWriter actually writes BIT_PACKED values. It would be better to relocate those classes in the rle and bitpacking packages.