### Question:
BitMapColumn extends BaseBitmapColumn { @Override public void release() { IoUtil.release(indexWriter, indexReader); indexWriter = null; indexReader = null; SwiftLoggers.getLogger().debug("swift bitmap released at {}", indexLocation.getPath()); } BitMapColumn(IResourceLocation parent); @Override void putBitMapIndex(int index, ImmutableBitMap bitmap); @Override void putNullIndex(ImmutableBitMap bitMap); @Override ImmutableBitMap getBitMapIndex(int index); @Override boolean isReadable(); @Override void release();  }### Answer:
@Test public void release() { BitMapColumn bitMapColumn = new BitMapColumn(new ResourceLocation("")); bitMapColumn.release(); verifyZeroInteractions(bitmapReader, bitmapWriter); bitMapColumn.putNullIndex(new EmptyBitmap()); bitMapColumn.getNullIndex(); bitMapColumn.release(); verify(bitmapWriter).release(); verify(bitmapReader).release(); }