diff --git a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
index b606bbb24..a19c9c41d 100644
--- a/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
+++ b/org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties
@@ -214,7 +214,6 @@ improperlyPaddedBase64Input=Improperly padded Base64 input.
 inMemoryBufferLimitExceeded=In-memory buffer limit exceeded
 incorrectHashFor=Incorrect hash for {0}; computed {1} as a {2} from {3} bytes.
 incorrectOBJECT_ID_LENGTH=Incorrect OBJECT_ID_LENGTH.
-incorrectObjectType_COMMITnorTREEnorBLOBnorTAG=COMMIT nor TREE nor BLOB nor TAG
 indexFileIsInUse=Index file is in use
 indexFileIsTooLargeForJgit=Index file is too large for jgit
 indexSignatureIsInvalid=Index signature is invalid: {0}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
index 5877b4f6a..f86a8e544 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
@@ -274,7 +274,6 @@ public static JGitText get() {
 	/***/ public String inMemoryBufferLimitExceeded;
 	/***/ public String incorrectHashFor;
 	/***/ public String incorrectOBJECT_ID_LENGTH;
-	/***/ public String incorrectObjectType_COMMITnorTREEnorBLOBnorTAG;
 	/***/ public String indexFileIsInUse;
 	/***/ public String indexFileIsTooLargeForJgit;
 	/***/ public String indexSignatureIsInvalid;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java
index bef5816b7..5f3599d8c 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java
@@ -139,9 +139,8 @@ public class PackWriter {
 	private static final int PACK_VERSION_GENERATED = 2;
 
 	@SuppressWarnings("unchecked")
-	private final List<ObjectToPack> objectsLists[] = new List[Constants.OBJ_TAG + 1];
+	private final BlockList<ObjectToPack> objectsLists[] = new BlockList[Constants.OBJ_TAG + 1];
 	{
-		objectsLists[0] = Collections.<ObjectToPack> emptyList();
 		objectsLists[Constants.OBJ_COMMIT] = new BlockList<ObjectToPack>();
 		objectsLists[Constants.OBJ_TREE] = new BlockList<ObjectToPack>();
 		objectsLists[Constants.OBJ_BLOB] = new BlockList<ObjectToPack>();
@@ -412,8 +411,12 @@ public void setTagTargets(Set<ObjectId> objects) {
 	public long getObjectCount() throws IOException {
 		if (stats.totalObjects == 0) {
 			long objCnt = 0;
-			for (List<ObjectToPack> list : objectsLists)
-				objCnt += list.size();
+
+			objCnt += objectsLists[Constants.OBJ_COMMIT].size();
+			objCnt += objectsLists[Constants.OBJ_TREE].size();
+			objCnt += objectsLists[Constants.OBJ_BLOB].size();
+			objCnt += objectsLists[Constants.OBJ_TAG].size();
+
 			for (CachedPack pack : cachedPacks)
 				objCnt += pack.getObjectCount();
 			return objCnt;
@@ -590,11 +593,16 @@ public void writeIndex(final OutputStream indexStream) throws IOException {
 	private List<ObjectToPack> sortByName() {
 		if (sortedByName == null) {
 			int cnt = 0;
-			for (List<ObjectToPack> list : objectsLists)
-				cnt += list.size();
+			cnt += objectsLists[Constants.OBJ_COMMIT].size();
+			cnt += objectsLists[Constants.OBJ_TREE].size();
+			cnt += objectsLists[Constants.OBJ_BLOB].size();
+			cnt += objectsLists[Constants.OBJ_TAG].size();
+
 			sortedByName = new BlockList<ObjectToPack>(cnt);
-			for (List<ObjectToPack> list : objectsLists)
-				sortedByName.addAll(list);
+			sortedByName.addAll(objectsLists[Constants.OBJ_COMMIT]);
+			sortedByName.addAll(objectsLists[Constants.OBJ_TREE]);
+			sortedByName.addAll(objectsLists[Constants.OBJ_BLOB]);
+			sortedByName.addAll(objectsLists[Constants.OBJ_TAG]);
 			Collections.sort(sortedByName);
 		}
 		return sortedByName;
@@ -707,20 +715,29 @@ public void release() {
 
 	private void searchForReuse(ProgressMonitor monitor) throws IOException {
 		int cnt = 0;
-		for (List<ObjectToPack> list : objectsLists)
-			cnt += list.size();
+		cnt += objectsLists[Constants.OBJ_COMMIT].size();
+		cnt += objectsLists[Constants.OBJ_TREE].size();
+		cnt += objectsLists[Constants.OBJ_BLOB].size();
+		cnt += objectsLists[Constants.OBJ_TAG].size();
+
 		long start = System.currentTimeMillis();
 		monitor.beginTask(JGitText.get().searchForReuse, cnt);
-		for (List<ObjectToPack> list : objectsLists) {
-			pruneCurrentObjectList = false;
-			reuseSupport.selectObjectRepresentation(this, monitor, list);
-			if (pruneCurrentObjectList)
-				pruneEdgesFromObjectList(list);
-		}
+		searchForReuse(monitor, objectsLists[Constants.OBJ_COMMIT]);
+		searchForReuse(monitor, objectsLists[Constants.OBJ_TREE]);
+		searchForReuse(monitor, objectsLists[Constants.OBJ_BLOB]);
+		searchForReuse(monitor, objectsLists[Constants.OBJ_TAG]);
 		monitor.endTask();
 		stats.timeSearchingForReuse = System.currentTimeMillis() - start;
 	}
 
+	private void searchForReuse(ProgressMonitor monitor, List<ObjectToPack> list)
+			throws IOException, MissingObjectException {
+		pruneCurrentObjectList = false;
+		reuseSupport.selectObjectRepresentation(this, monitor, list);
+		if (pruneCurrentObjectList)
+			pruneEdgesFromObjectList(list);
+	}
+
 	private void searchForDeltas(ProgressMonitor monitor)
 			throws MissingObjectException, IncorrectObjectTypeException,
 			IOException {
@@ -1472,25 +1489,14 @@ public void addObject(final RevObject object)
 		addObject(object, 0);
 	}
 
-	private void addObject(final RevObject object, final int pathHashCode)
-			throws IncorrectObjectTypeException {
+	private void addObject(final RevObject object, final int pathHashCode) {
 		final ObjectToPack otp;
 		if (reuseSupport != null)
 			otp = reuseSupport.newObjectToPack(object);
 		else
 			otp = new ObjectToPack(object);
 		otp.setPathHash(pathHashCode);
-
-		try {
-			objectsLists[object.getType()].add(otp);
-		} catch (ArrayIndexOutOfBoundsException x) {
-			throw new IncorrectObjectTypeException(object,
-					JGitText.get().incorrectObjectType_COMMITnorTREEnorBLOBnorTAG);
-		} catch (UnsupportedOperationException x) {
-			// index pointing to "dummy" empty list
-			throw new IncorrectObjectTypeException(object,
-					JGitText.get().incorrectObjectType_COMMITnorTREEnorBLOBnorTAG);
-		}
+		objectsLists[object.getType()].add(otp);
 		objectsMap.add(otp);
 	}