diff --git a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/util/ExtMXSerializer.java b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/util/ExtMXSerializer.java
index bba69d82..5e15985f 100644
--- a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/util/ExtMXSerializer.java
+++ b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/util/ExtMXSerializer.java
@@ -26,16 +26,14 @@ public class ExtMXSerializer extends MXSerializer implements ExtXmlSerializer {
     @Override
     public void startDocument(String encoding, Boolean standalone)
             throws IOException, IllegalArgumentException, IllegalStateException {
-        super.startDocument(encoding != null ? encoding : mDefaultEncoding,
-                standalone);
+        super.startDocument(encoding != null ? encoding : mDefaultEncoding, standalone);
         this.newLine();
     }
 
     @Override
-    protected void writeAttributeValue(String value, Writer out)
-            throws IOException {
+    protected void writeAttributeValue(String value, Writer out) throws IOException {
         if (mIsDisabledAttrEscape) {
-            out.write(value);
+            out.write(value == null ? "" : value);
             return;
         }
         super.writeAttributeValue(value, out);
@@ -55,8 +53,7 @@ public class ExtMXSerializer extends MXSerializer implements ExtXmlSerializer {
     }
 
     @Override
-    public void setProperty(String name, Object value)
-            throws IllegalArgumentException, IllegalStateException {
+    public void setProperty(String name, Object value) throws IllegalArgumentException, IllegalStateException {
         if (PROPERTY_DEFAULT_ENCODING.equals(name)) {
             mDefaultEncoding = (String) value;
         } else {
diff --git a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/xml/ResXmlEncoders.java b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/xml/ResXmlEncoders.java
index 8cf7bdb4..ded03e12 100644
--- a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/xml/ResXmlEncoders.java
+++ b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/xml/ResXmlEncoders.java
@@ -34,7 +34,7 @@ public final class ResXmlEncoders {
     }
 
     public static String encodeAsResXmlAttr(String str) {
-        if (str.isEmpty()) {
+        if (str == null || str.isEmpty()) {
             return str;
         }