move Diff utility to test classes

git-svn-id: https://svn.apache.org/repos/asf/xmlbeans/trunk@1881991 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/src/main/java/org/apache/xmlbeans/impl/util/HexBin.java b/src/main/java/org/apache/xmlbeans/impl/util/HexBin.java
index 60d607e..3e84f9c 100644
--- a/src/main/java/org/apache/xmlbeans/impl/util/HexBin.java
+++ b/src/main/java/org/apache/xmlbeans/impl/util/HexBin.java
@@ -25,8 +25,8 @@
 public final class HexBin {
     static private final int BASELENGTH = 255;
     static private final int LOOKUPLENGTH = 16;
-    static private byte[] hexNumberTable = new byte[BASELENGTH];
-    static private byte[] lookUpHexAlphabet = new byte[LOOKUPLENGTH];
+    static private final byte[] hexNumberTable = new byte[BASELENGTH];
+    static private final byte[] lookUpHexAlphabet = new byte[LOOKUPLENGTH];
 
 
     static {
diff --git a/src/main/java/org/apache/xmlbeans/impl/tool/Diff.java b/src/test/java/org/apache/xmlbeans/impl/tool/Diff.java
similarity index 100%
rename from src/main/java/org/apache/xmlbeans/impl/tool/Diff.java
rename to src/test/java/org/apache/xmlbeans/impl/tool/Diff.java