Index: core/logging/src/main/java/com/sun/enterprise/server/logging/UniformLogFormatter.java
===================================================================
--- core/logging/src/main/java/com/sun/enterprise/server/logging/UniformLogFormatter.java	(revision 45202)
+++ core/logging/src/main/java/com/sun/enterprise/server/logging/UniformLogFormatter.java	(working copy)
@@ -205,13 +205,32 @@
                 }
                 if (obj instanceof Map) {
                     for (Map.Entry<Object, Object> entry : ((Map<Object, Object>) obj).entrySet()) {
-                        buf.append(entry.getKey().toString()).append(NV_SEPARATOR).
-                                append(entry.getValue().toString()).
-                                append(NVPAIR_SEPARATOR);
+                        // there are implementations that allow <null> keys...
+                        if(entry.getKey() != null) {
+                            buf.append(entry.getKey().toString());
+                        } else {
+                            buf.append("null");
+                        }
+
+                        buf.append(NV_SEPARATOR);
+
+                        // also handle <null> values...
+                        if(entry.getValue() != null) {
+                            buf.append(entry.getValue().toString());
+                        } else {
+                            buf.append("null");
+                        }
+                        buf.append(NVPAIR_SEPARATOR);
                     }
                 } else if (obj instanceof java.util.Collection) {
                     for (Object entry : ((Collection) obj)) {
-                        buf.append(entry.toString()).append(NVPAIR_SEPARATOR);
+                        // handle null values (remember the specs)...
+                        if(entry != null) {
+                            buf.append(entry.toString());
+                        } else {
+                            buf.append("null");
+                        }
+                        buf.append(NVPAIR_SEPARATOR);
                     }
 //                } else {
 //                    buf.append(obj.toString()).append(NVPAIR_SEPARATOR);