The discussion about NDC vs. MDC has been done going for quite a while. I don't think MDC is a suitable replacement for NDC, except insofar as NDC can be implemented using MDC.

Enclosed is the NDC implementation we're started using at Electric Cloud. Please feel free to adapt/modify/enhance it as you see fit. We place this code in the public domain in case others find it useful.

Attachment to come as well.

// NDC.java –
//
// NDC.java is part of the ElectricCommander server.
//
// Copyright (c) 2005-2009 Electric Cloud, Inc.
// All rights reserved.
//

package com.electriccloud.log;

import java.util.Deque;
import java.util.LinkedList;

import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;

import org.slf4j.MDC;

/**

• Utility object that implements NDC using MDC.
  */
  @SuppressWarnings( {"UtilityClass", "StringContatenationInLoop"}

  )
  public class NDC
  {

//~ Static fields/initializers ---------------------------------------------

private static final ThreadLocal<Deque<String>> s_stack =
new ThreadLocal<Deque<String>>() {
@Override @SuppressWarnings(

{"RefusedBequest"}

)
protected Deque<String> initialValue()

{ return new LinkedList<String>(); }

};

//~ Constructors -----------------------------------------------------------

private NDC()
{
}

//~ Methods ----------------------------------------------------------------

public static void pop()
{
Deque<String> stack = s_stack.get();

// Pop the stack if isn't already empty
if (!stack.isEmpty())

{ stack.pop(); }

// Put the previous value in the MDC (null if the stack is now empty)
MDC.put("NDC", stack.peek());
}

@SuppressWarnings(

{"HardCodedStringLiteral"}

)
public static void push(@NonNls @NotNull String format, Object... args)

{ Deque<String> stack = s_stack.get(); String previous = stack.peek(); String segment = args.length == 0 ? format : String.format(format, args); String newValue = previous == null ? segment : String.format("%s %s", previous, segment); stack.push(newValue); MDC.put("NDC", newValue); }

}