@Override
  public void append(LogEvent logEvent) {
    EVENTS.add(logEvent);
  }
A log appender which captures the log events. This is useful for testing if log events
are being logged correctly and at correct levels.
standalone-metastore/metastore-server/src/test/java/org/apache/hadoop/hive/metastore/testutils/CapturingLogAppender.java