### Question:
ReconOmMetadataManagerImpl extends OmMetadataManagerImpl implements ReconOMMetadataManager { @Override public void updateOmDB(File newDbLocation) throws IOException { if (getStore() != null) { File oldDBLocation = getStore().getDbLocation(); if (oldDBLocation.exists()) { LOG.info("Cleaning up old OM snapshot db at {}.", oldDBLocation.getAbsolutePath()); FileUtils.deleteDirectory(oldDBLocation); } } initializeNewRdbStore(newDbLocation); } @Inject  ReconOmMetadataManagerImpl(OzoneConfiguration configuration,
                                    ReconUtils reconUtils); @Override void start(OzoneConfiguration configuration); @Override void updateOmDB(File newDbLocation); @Override long getLastSequenceNumberFromDB(); @Override boolean isOmTablesInitialized();  }### Answer:
@Test public void testUpdateOmDB() throws Exception { OMMetadataManager omMetadataManager = getOMMetadataManager(); Assert.assertNotNull(omMetadataManager.getKeyTable() .get("/sampleVol/bucketOne/key_one")); Assert.assertNotNull(omMetadataManager.getKeyTable() .get("/sampleVol/bucketOne/key_two")); DBCheckpoint checkpoint = omMetadataManager.getStore() .getCheckpoint(true); Assert.assertNotNull(checkpoint.getCheckpointLocation()); File reconOmDbDir = temporaryFolder.newFolder(); OzoneConfiguration configuration = new OzoneConfiguration(); configuration.set(OZONE_RECON_OM_SNAPSHOT_DB_DIR, reconOmDbDir .getAbsolutePath()); ReconOMMetadataManager reconOMMetadataManager = new ReconOmMetadataManagerImpl(configuration, new ReconUtils()); reconOMMetadataManager.start(configuration); Assert.assertNull(reconOMMetadataManager.getBucketTable()); reconOMMetadataManager.updateOmDB( checkpoint.getCheckpointLocation().toFile()); Assert.assertNotNull(reconOMMetadataManager.getBucketTable()); Assert.assertNotNull(reconOMMetadataManager.getVolumeTable() .get("/sampleVol")); Assert.assertNotNull(reconOMMetadataManager.getBucketTable() .get("/sampleVol/bucketOne")); Assert.assertNotNull(reconOMMetadataManager.getKeyTable() .get("/sampleVol/bucketOne/key_one")); Assert.assertNotNull(reconOMMetadataManager.getKeyTable() .get("/sampleVol/bucketOne/key_two")); }