How to customize java.util.logging.Logger class to write logs in separate file than System.out.log in Websphere commerce/ HCL commerce)

/**

* This method updated the passed in java.util.logging.Logger object with

* custom file handler to write logs data form that class in separate file.

* 

*  1. New log file name patter is NewLogFile_%g.log where %g is sequential number starting with 0

*  2. New Log file size max limit is 25MB after that system will rotate log in new file where %g is replaced by next sequence

*  3. From log request/response message all new line, space  and tabs characters are removed

*  4. To enable/disable logging we still use OOB WAS admin console Logs & Trace configuration

*  5. To enable logging for a class in separate file add log level as "com.xyz.XYZClassName=fine"

*     in WAS admin console Logs & Trace configuration

*  6. To disable logging remove above log level from logs configuration in WAS admin console

*  7. Max number of new log files count is 20 as passed in new FileHandler argument

*  8. String.format("[%1$tF %1$tT %1$tZ] ",new Date(record.getMillis())) will format date as [2021-10-01 15:24:26 BST]

*  

* @param logger java.util.logging.Logger lass object obtained like Logger.getLogger(CLASSNAME)

* @param newLogFile: newLogFile = System.getenv("USER_INSTALL_ROOT")+"\\logs\\server1\\NewLogFile_%g.log"

*/

public static void updateLoggerWithCustomHandler(Logger logger,String newLogFile) {

try {

Handler fileHandler = new FileHandler(newLogFile, 25000000, 20,true);

fileHandler.setFormatter(new SimpleFormatter() {

      

      @Override

      public String format(LogRecord record) {

          StringBuilder sb = new StringBuilder();

          sb.append(String.format("[%1$tF %1$tT %1$tZ] ",new Date(record.getMillis())));

          sb.append(String.format("%1$08x",record.getThreadID())).append(" ");

          sb.append(record.getSourceClassName()).append(" ");

          sb.append(record.getSourceMethodName()).append(" ");

          sb.append(record.getMessage().replaceAll("[\\n\\t\\s]", ""));

          sb.append(System.getProperty("line.separator"));

          if (null != record.getThrown()) {

              sb.append("Throwable occurred: ");

              Throwable thrown = record.getThrown();

              PrintWriter printWriter = null;

              try {

                  StringWriter stringWriter = new StringWriter();

                  printWriter = new PrintWriter(stringWriter);

                  thrown.printStackTrace(printWriter);

                  sb.append(stringWriter.toString());

              } finally {

                  if (printWriter != null) {

                      try {

                      printWriter.close();

                      } catch (Exception e) {

                          // ignore

                      }

                  }

              }

          }

          return sb.toString();

      }

      

    });

 

logger.setUseParentHandlers(false);

logger.addHandler(fileHandler);

} catch (IOException e) {

//Error while creating separate log file for OS api logging

}

  }

NOTE: call above defined static method updateLoggerWithCustomHandler  static block on class which requires logger update and logger  object should be fetched as public static class level instance variable like Logger LOGGER = Logger.getLogger(CLASSNAME);