Index: src/java/com/thoughtworks/xstream/XStream.java
===================================================================
--- src/java/com/thoughtworks/xstream/XStream.java	(révision 1726)
+++ src/java/com/thoughtworks/xstream/XStream.java	(copie de travail)
@@ -651,7 +651,9 @@
         registerConverter(new MapConverter(mapper), PRIORITY_NORMAL);
         registerConverter(new TreeMapConverter(mapper), PRIORITY_NORMAL);
         registerConverter(new TreeSetConverter(mapper), PRIORITY_NORMAL);
-        registerConverter(new PropertiesConverter(), PRIORITY_NORMAL);
+        if(!jvm.isAppEngine()){
+        	registerConverter(new PropertiesConverter(), PRIORITY_NORMAL);
+        }
         registerConverter(new EncodedByteArrayConverter(), PRIORITY_NORMAL);
 
         registerConverter(new FileConverter(), PRIORITY_NORMAL);
@@ -668,7 +670,9 @@
         if (jvm.supportsAWT()) {
             registerConverter(new FontConverter(), PRIORITY_NORMAL);
             registerConverter(new ColorConverter(), PRIORITY_NORMAL);
-            registerConverter(new TextAttributeConverter(), PRIORITY_NORMAL);
+            if(!jvm.isAppEngine()){
+            	registerConverter(new TextAttributeConverter(), PRIORITY_NORMAL);
+            }
         }
         if (jvm.supportsSwing()) {
             registerConverter(
@@ -709,13 +713,16 @@
             dynamicallyRegisterConverter(
                 "com.thoughtworks.xstream.converters.enums.EnumConverter", PRIORITY_NORMAL,
                 null, null);
+            
+            if(!jvm.isAppEngine()){
+	            	dynamicallyRegisterConverter(
+	                "com.thoughtworks.xstream.converters.enums.EnumSetConverter", PRIORITY_NORMAL,
+	                new Class[]{Mapper.class}, new Object[]{mapper});
+	            dynamicallyRegisterConverter(
+	                "com.thoughtworks.xstream.converters.enums.EnumMapConverter", PRIORITY_NORMAL,
+	                new Class[]{Mapper.class}, new Object[]{mapper});
+            }
             dynamicallyRegisterConverter(
-                "com.thoughtworks.xstream.converters.enums.EnumSetConverter", PRIORITY_NORMAL,
-                new Class[]{Mapper.class}, new Object[]{mapper});
-            dynamicallyRegisterConverter(
-                "com.thoughtworks.xstream.converters.enums.EnumMapConverter", PRIORITY_NORMAL,
-                new Class[]{Mapper.class}, new Object[]{mapper});
-            dynamicallyRegisterConverter(
                 "com.thoughtworks.xstream.converters.basic.StringBuilderConverter",
                 PRIORITY_NORMAL, null, null);
             dynamicallyRegisterConverter(
Index: src/java/com/thoughtworks/xstream/core/JVM.java
===================================================================
--- src/java/com/thoughtworks/xstream/core/JVM.java	(révision 1726)
+++ src/java/com/thoughtworks/xstream/core/JVM.java	(copie de travail)
@@ -34,6 +34,8 @@
     private static final float majorJavaVersion = getMajorJavaVersion();
     private static final boolean reverseFieldOrder = isHarmony() || (isIBM() && !is15());
 
+    private final boolean isAppEngine = loadClass("com.google.appengine.api.datastore.DatastoreService") != null;
+    
     static final float DEFAULT_JAVA_VERSION = 1.3f;
 
     /**
@@ -95,6 +97,7 @@
         return vendor.indexOf("Android") != -1;
     }
 
+    
     /*
      * Support for sun.misc.Unsafe and sun.reflect.ReflectionFactory is present
      * in JRockit versions R25.1.0 and later, both 1.4.2 and 5.0 (and in future
@@ -142,6 +145,10 @@
         return vendor.indexOf("SAP AG") != -1;
     }
 
+    public boolean isAppEngine() {
+		return isAppEngine;
+	}
+    
     public Class loadClass(String name) {
         try {
             WeakReference reference = (WeakReference) loaderCache.get(name);