ADDITIONAL SYSTEM INFORMATION :
OS: Windows10, Fedora35
Java ( jdk.java.net ): 1.8.0.322, 18.0.1
div Hardware, Laptops, Desktops, Intel i5-3k... / i7-10k...

A DESCRIPTION OF THE PROBLEM :
When using a custom properties-file to set the configuration for java.util.logging (example, see below link) the configured custom MemoryHandler is set up with a custom Formatter (also see below link regarding the api-documentation). The target of the CustomMemoryHandler id directed to the std ConsoleHandler (using the default-formatter).
The problem is, the CustomMemoryHandler does not format any log-message.
Workaround: Enabling the CustomFormatter on the ConsoleHandler gets the output formatted.

API-Documantation: https://docs.oracle.com/en/java/javase/18/docs/api/java.logging/java/util/logging/MemoryHandler.html
Example on github: https://github.com/SvenJunge/memoryhandler-eval

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See code from github repo.
Run: foo.Main
For Workaround change loaded resource/properties-file (logging.properties.nocustomformat vs. logging.properties.customformat ).



EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The log-messages printed to console should be formatted by the CustomFormatter (one line, level: message).
ACTUAL -
The log-messages printed to console are formatted with standard-formatter (two lines, localized level, class-name, method-name).

---------- BEGIN SOURCE ----------
https://github.com/SvenJunge/memoryhandler-eval
------------------------
## CustomFormatter.java
package foo;


import java.util.logging.Formatter;
import java.util.logging.LogRecord;


public final
class CustomFormatter
    extends Formatter
{

  @Override
  public String
  format( final LogRecord record )
  {
    return record.getLevel() + ":\t\t" + record.getMessage() + System.lineSeparator();
  }

}
-----------------------
## CustomMemoryHandler.java
package foo;


import java.util.logging.MemoryHandler;


public final
class CustomMemoryHandler
    extends MemoryHandler
{

  @Override
  public void
  close()
      throws SecurityException
  {
    super.push();
    super.flush();
    super.close();
  }

}
------------------------
## Main.java
package foo;


import java.io.IOException;
import java.io.InputStream;
import java.util.logging.LogManager;
import java.util.logging.Logger;


public final
class Main
{

  public static void
  main( final String[] args )
      throws InterruptedException
           , IOException
  {
    System.out.println( "Starting ..." );

    try ( final InputStream is = Main.class.getClassLoader()
                                           .getResourceAsStream( "logging.properties.nocustomformat" ) )
// .getResourceAsStream( "logging.properties.customformat" ) )
    {
      LogManager.getLogManager()
                .readConfiguration( is );
    }

    final Logger log = Logger.getLogger( Main.class.getName() );

    for( int i = 1; i <= 3; i++ )
    {
      System.out.println( "run: " + i );
      Thread.sleep( 200L );

      log.config( "config-msg" );
      log.info( "info-msg" );
      if( i % 2 == 0)
      { log.warning( "warning-msg" ); }

      System.out.println( "sleep" );
      Thread.sleep( 650L );
    }

    System.out.println( "-fin. (CustomMemoryHandler.close() should invoke publish+flush)" );
  }

}
--------------------------------
## logging.properties.nocustomformat
#.level = ALL
#.handler = java.util.logging.ConsoleHandler

java.util.logging.ConsoleHandler.level = CONFIG
#java.util.logging.ConsoleHandler.formatter = foo.CustomFormatter

foo.level = ALL
foo.handlers = foo.CustomMemoryHandler

foo.CustomMemoryHandler.formatter = foo.CustomFormatter
foo.CustomMemoryHandler.target = java.util.logging.ConsoleHandler
foo.CustomMemoryHandler.push = WARNING

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Adding the CustomFormatter to the ConsoleHandler.

FREQUENCY : always