Java (Hotspot) class layout printer.

FieldLayoutPrinter.java

import sun.misc.Unsafe;
import java.lang.reflect.*;
import java.util.*;

class FieldLayoutPrinter {
  private static Unsafe _unsafe = null;
  static {
    try {
      Field field = Unsafe.class.getDeclaredField("theUnsafe");
      field.setAccessible(true);
      _unsafe = (Unsafe)field.get(null);
    } catch (Exception e) {
      System.out.println("ERROR: Couldn't reflect on sun.misc.Unsafe.");
    }
  }

  static List<Field> get_field_list(final Class klass)
  {
    List<Field> fields = null;
    if (!klass.isPrimitive()) {
      fields = new ArrayList<Field>();
      Class current = klass;
      while (current != null) {
        Collections.addAll(fields, current.getDeclaredFields());
        current = (current == Object.class) ? null: current.getSuperclass();
      }
    }

    return fields;
  }

  static void print_field_list(final Object o)
  {
    for (final Field field: get_field_list(o.getClass())) {
      if ((field.getModifiers() & Modifier.STATIC) != 0) continue;
      System.out.println(_unsafe.objectFieldOffset(field)    +
                         " " +
                         field.getDeclaringClass().getName() +
                         "::" +
                         field.getName());
    }
  }

  public static void main(String[] args)
  {
    print_field_list("Hello, World!");
  }
};