code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC licenses this file
  // to you under the Apache License, Version 2.0 (the
  // "License"); you may not use this file except in compliance
  // with the License.  You may obtain a copy of the License at
  //
  //   http://www.apache.org/licenses/LICENSE-2.0
  //
  // Unless required by applicable law or agreed to in writing,
  // software distributed under the License is distributed on an
  // "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  // KIND, either express or implied.  See the License for the
  // specific language governing permissions and limitations
  // under the License.
  
  package org.openqa.selenium.grid.log;
  
  import static java.time.ZoneOffset.UTC;
  import static java.time.format.DateTimeFormatter.ISO_OFFSET_DATE_TIME;
  
  import java.time.Instant;
  import java.time.ZoneId;
  import java.time.ZonedDateTime;
  import java.util.Map;
  import java.util.TreeMap;
  import java.util.logging.Formatter;
  import java.util.logging.LogRecord;
  import org.openqa.selenium.json.Json;
  import org.openqa.selenium.json.JsonOutput;
  
  class JsonFormatter extends Formatter {
  
    public static final Json JSON = new Json();
  
    @Override
    public String format(LogRecord record) {
      Map<String, Object> logRecord = new TreeMap<>();
  
      Instant instant = Instant.ofEpochMilli(record.getMillis());
      ZonedDateTime local = ZonedDateTime.ofInstant(instant, ZoneId.systemDefault());
  
      logRecord.put("log-time-local", ISO_OFFSET_DATE_TIME.format(local));
      logRecord.put("log-time-utc", ISO_OFFSET_DATE_TIME.format(local.withZoneSameInstant(UTC)));
  
      String[] split = record.getSourceClassName().split("\\.");
      logRecord.put("class", split[split.length - 1]);
      logRecord.put("method", record.getSourceMethodName());
      logRecord.put("log-name", record.getLoggerName());
      logRecord.put("log-level", record.getLevel());
      logRecord.put("log-message", record.getMessage());
  
      StringBuilder text = new StringBuilder();
      try (JsonOutput json = JSON.newOutput(text).setPrettyPrint(false)) {
        json.write(logRecord);
        text.append('\n');
      }
      return text.toString();
    }
  }
  