### Question:
LogSubcommand extends BaseInsightSubCommand implements Callable<Void> { public String processLogLine(String line) { Pattern p = Pattern.compile("<json>(.*)</json>"); Matcher m = p.matcher(line); StringBuffer sb = new StringBuffer(); while (m.find()) { m.appendReplacement(sb, "\n" + m.group(1).replaceAll("\\\\n", "\n")); } m.appendTail(sb); return sb.toString(); }  @Override Void call(); String processLogLine(String line);  }### Answer:
@Test public void filterLog() { LogSubcommand logSubcommand = new LogSubcommand(); String result = logSubcommand.processLogLine( "2020-03-12 20:57:54,001 [TRACE|org.apache.hadoop.hdds.scm.node" + ".SCMNodeManager|SCMNodeManager] HB is received from " + "[datanode=localhost]: <json>storageReport {\\n storageUuid: " + "\"DS-f65eb957-fc2d-4b77-b4a3-e96ae2bd2ca6\"\\n " + "storageLocation: \"/tmp/hadoop-neo/dfs/data\"\\n capacity: " + "250438021120\\n scmUsed: 16384\\n remaining: 212041244672\\n " + "storageType: DISK\\n failed: false\\n}\\n</json>"); Assert.assertEquals(10, result.split("\n").length); }