diff --git a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
index 858fe64a6..2737b6483 100644
--- a/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
+++ b/org.eclipse.jgit.junit/src/org/eclipse/jgit/junit/TestRepository.java
@@ -359,7 +359,7 @@ public class TestRepository<R extends Repository> {
 			final RevCommit... parents) throws Exception {
 		tick(secDelta);
 
-		final Commit c = new Commit(db);
+		final Commit c = new Commit();
 		c.setTreeId(tree);
 		c.setParentIds(parents);
 		c.setAuthor(new PersonIdent(author, new Date(now)));
@@ -811,8 +811,8 @@ public class TestRepository<R extends Repository> {
 			if (self == null) {
 				TestRepository.this.tick(tick);
 
-				final Commit c = new Commit(db);
-				c.setParentIds(parents.toArray(new RevCommit[parents.size()]));
+				final Commit c = new Commit();
+				c.setParentIds(parents);
 				c.setAuthor(new PersonIdent(author, new Date(now)));
 				c.setCommitter(new PersonIdent(committer, new Date(now)));
 				c.setMessage(message);
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
index 22302bba8..1b1a8c28e 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/Clone.java
@@ -51,11 +51,10 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
-import org.kohsuke.args4j.Argument;
-import org.kohsuke.args4j.Option;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.NotSupportedException;
 import org.eclipse.jgit.errors.TransportException;
-import org.eclipse.jgit.lib.Commit;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.GitIndex;
 import org.eclipse.jgit.lib.Ref;
@@ -64,12 +63,16 @@ import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.TextProgressMonitor;
 import org.eclipse.jgit.lib.Tree;
 import org.eclipse.jgit.lib.WorkDirCheckout;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.file.FileRepository;
 import org.eclipse.jgit.transport.FetchResult;
 import org.eclipse.jgit.transport.RefSpec;
 import org.eclipse.jgit.transport.RemoteConfig;
 import org.eclipse.jgit.transport.Transport;
 import org.eclipse.jgit.transport.URIish;
+import org.kohsuke.args4j.Argument;
+import org.kohsuke.args4j.Option;
 
 @Command(common = true, usage = "usage_cloneRepositoryIntoNewDir")
 class Clone extends AbstractFetchCommand {
@@ -174,17 +177,30 @@ class Clone extends AbstractFetchCommand {
 			u.link(branch.getName());
 		}
 
-		final Commit commit = db.mapCommit(branch.getObjectId());
+		final RevCommit commit = parseCommit(branch);
 		final RefUpdate u = db.updateRef(Constants.HEAD);
-		u.setNewObjectId(commit.getCommitId());
+		u.setNewObjectId(commit);
 		u.forceUpdate();
 
 		final GitIndex index = new GitIndex(db);
-		final Tree tree = commit.getTree();
+		final Tree tree = db.mapTree(commit.getTree());
 		final WorkDirCheckout co;
 
 		co = new WorkDirCheckout(db, db.getWorkTree(), index, tree);
 		co.checkout();
 		index.write();
 	}
+
+	private RevCommit parseCommit(final Ref branch)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		final RevWalk rw = new RevWalk(db);
+		final RevCommit commit;
+		try {
+			commit = rw.parseCommit(branch.getObjectId());
+		} finally {
+			rw.release();
+		}
+		return commit;
+	}
 }
\ No newline at end of file
diff --git a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildCommitGraph.java b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildCommitGraph.java
index b8e2a8f6f..e0a743356 100644
--- a/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildCommitGraph.java
+++ b/org.eclipse.jgit.pgm/src/org/eclipse/jgit/pgm/debug/RebuildCommitGraph.java
@@ -56,26 +56,25 @@ import java.util.List;
 import java.util.ListIterator;
 import java.util.Map;
 
-import org.kohsuke.args4j.Argument;
-import org.kohsuke.args4j.Option;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.errors.ObjectWritingException;
 import org.eclipse.jgit.lib.Commit;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectIdRef;
-import org.eclipse.jgit.lib.ObjectWriter;
+import org.eclipse.jgit.lib.ObjectInserter;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.RefWriter;
 import org.eclipse.jgit.lib.TextProgressMonitor;
-import org.eclipse.jgit.lib.Tree;
 import org.eclipse.jgit.pgm.CLIText;
 import org.eclipse.jgit.pgm.TextBuiltin;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.storage.file.LockFile;
+import org.kohsuke.args4j.Argument;
+import org.kohsuke.args4j.Option;
 
 /**
  * Recreates a repository from another one's commit graph.
@@ -164,8 +163,8 @@ class RebuildCommitGraph extends TextBuiltin {
 		}
 
 		pm.beginTask("Rewriting commits", queue.size());
-		final ObjectWriter ow = new ObjectWriter(db);
-		final ObjectId emptyTree = ow.writeTree(new Tree(db));
+		final ObjectInserter oi = db.newObjectInserter();
+		final ObjectId emptyTree = oi.insert(Constants.OBJ_TREE, new byte[] {});
 		final PersonIdent me = new PersonIdent("jgit rebuild-commitgraph",
 				"rebuild-commitgraph@localhost");
 		while (!queue.isEmpty()) {
@@ -192,17 +191,19 @@ class RebuildCommitGraph extends TextBuiltin {
 					}
 				}
 
-				final Commit newc = new Commit(db);
+				final Commit newc = new Commit();
 				newc.setTreeId(emptyTree);
 				newc.setAuthor(new PersonIdent(me, new Date(t.commitTime)));
 				newc.setCommitter(newc.getAuthor());
 				newc.setParentIds(newParents);
 				newc.setMessage("ORIGINAL " + t.oldId.name() + "\n");
-				t.newId = ow.writeCommit(newc);
+				t.newId = oi.insert(Constants.OBJ_COMMIT,oi.format(newc));
 				rewrites.put(t.oldId, t.newId);
 				pm.update(1);
 			}
 		}
+		oi.flush();
+		oi.release();
 		pm.endTask();
 	}
 
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
index 773d2f055..ccb1672dd 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/MergeCommandTest.java
@@ -155,8 +155,8 @@ public class MergeCommandTest extends RepositoryTestCase {
 		File workDir = db.getWorkTree();
 		if (workDir != null) {
 			WorkDirCheckout workDirCheckout = new WorkDirCheckout(db,
-					workDir, db.mapCommit(Constants.HEAD).getTree(),
-					db.getIndex(), db.mapCommit(branchName).getTree());
+					workDir, db.mapTree(Constants.HEAD),
+					db.getIndex(), db.mapTree(branchName));
 			workDirCheckout.setFailOnConflict(true);
 			try {
 				workDirCheckout.checkout();
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ReflogConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ReflogConfigTest.java
index d78892b89..5001b8fc7 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ReflogConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/ReflogConfigTest.java
@@ -104,11 +104,11 @@ public class ReflogConfigTest extends RepositoryTestCase {
 
 	private void commit(final Tree t, String commitMsg, PersonIdent author,
 			PersonIdent committer) throws IOException {
-		final Commit commit = new Commit(db);
+		final Commit commit = new Commit();
 		commit.setAuthor(author);
 		commit.setCommitter(committer);
 		commit.setMessage(commitMsg);
-		commit.setTree(t);
+		commit.setTreeId(t.getTreeId());
 		ObjectWriter writer = new ObjectWriter(db);
 		commit.setCommitId(writer.writeCommit(commit));
 
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/CherryPickTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/CherryPickTest.java
index 1cd126163..977c9216e 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/CherryPickTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/CherryPickTest.java
@@ -131,7 +131,7 @@ public class CherryPickTest extends RepositoryTestCase {
 
 	private ObjectId commit(final ObjectInserter odi, final DirCache treeB,
 			final ObjectId[] parentIds) throws Exception {
-		final Commit c = new Commit(db);
+		final Commit c = new Commit();
 		c.setTreeId(treeB.writeTree(odi));
 		c.setAuthor(new PersonIdent("A U Thor", "a.u.thor", 1L, 0));
 		c.setCommitter(c.getAuthor());
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SimpleMergeTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SimpleMergeTest.java
index 8657c52b1..88959c792 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SimpleMergeTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/SimpleMergeTest.java
@@ -367,7 +367,7 @@ public class SimpleMergeTest extends SampleDataRepositoryTestCase {
 
 	private ObjectId commit(final ObjectInserter odi, final DirCache treeB,
 			final ObjectId[] parentIds) throws Exception {
-		final Commit c = new Commit(db);
+		final Commit c = new Commit();
 		c.setTreeId(treeB.writeTree(odi));
 		c.setAuthor(new PersonIdent("A U Thor", "a.u.thor", 1L, 0));
 		c.setCommitter(c.getAuthor());
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/T0003_Basic.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/T0003_Basic.java
index dfdffaa6a..0c170a6b3 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/T0003_Basic.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/storage/file/T0003_Basic.java
@@ -53,15 +53,20 @@ import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.PrintWriter;
+import java.io.UnsupportedEncodingException;
 
 import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.Commit;
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.FileTreeEntry;
 import org.eclipse.jgit.lib.ObjectDatabase;
 import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.ObjectInserter;
 import org.eclipse.jgit.lib.ObjectWriter;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.RefUpdate;
@@ -71,6 +76,8 @@ import org.eclipse.jgit.lib.Tag;
 import org.eclipse.jgit.lib.Tree;
 import org.eclipse.jgit.lib.TreeEntry;
 import org.eclipse.jgit.lib.WriteTree;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevWalk;
 
 public class T0003_Basic extends SampleDataRepositoryTestCase {
 	public void test001_Initalize() {
@@ -243,7 +250,8 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		assertEqualsPath(theDir.getParentFile(), r.getWorkTree());
 		assertEqualsPath(indexFile, r.getIndexFile());
 		assertEqualsPath(objDir, r.getObjectDatabase().getDirectory());
-		assertNotNull(r.mapCommit("6db9c2ebf75590eef973081736730a9ea169a0c4"));
+		assertNotNull(r.open(ObjectId
+				.fromString("6db9c2ebf75590eef973081736730a9ea169a0c4")));
 		// Must close or the default repo pack files created by this test gets
 		// locked via the alternate object directories on Windows.
 		r.close();
@@ -374,13 +382,15 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		assertEquals(ObjectId.fromString("00b1f73724f493096d1ffa0b0f1f1482dbb8c936"),
 				t.getTreeId());
 
-		final Commit c = new Commit(db);
+		final Commit c = new Commit();
 		c.setAuthor(new PersonIdent(author, 1154236443000L, -4 * 60));
 		c.setCommitter(new PersonIdent(committer, 1154236443000L, -4 * 60));
 		c.setMessage("A Commit\n");
-		c.setTree(t);
+		c.setTreeId(t.getTreeId());
 		assertEquals(t.getTreeId(), c.getTreeId());
-		c.commit();
+
+		insertCommit(c);
+
 		final ObjectId cmtid = ObjectId.fromString(
 				"803aec4aba175e8ab1d666873c984c0308179099");
 		assertEquals(cmtid, c.getCommitId());
@@ -399,12 +409,12 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		}
 
 		// Verify we can read it.
-		final Commit c2 = db.mapCommit(cmtid);
+		RevCommit c2 = parseCommit(c.getCommitId());
 		assertNotNull(c2);
-		assertEquals(c.getMessage(), c2.getMessage());
-		assertEquals(c.getTreeId(), c2.getTreeId());
-		assertEquals(c.getAuthor(), c2.getAuthor());
-		assertEquals(c.getCommitter(), c2.getCommitter());
+		assertEquals(c.getMessage(), c2.getFullMessage());
+		assertEquals(c.getTreeId(), c2.getTree());
+		assertEquals(c.getAuthor(), c2.getAuthorIdent());
+		assertEquals(c.getCommitter(), c2.getCommitterIdent());
 	}
 
 	public void test012_SubtreeExternalSorting() throws IOException {
@@ -484,12 +494,12 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		final Tree almostEmptyTree = new Tree(db);
 		almostEmptyTree.addEntry(new FileTreeEntry(almostEmptyTree, emptyId, "empty".getBytes(), false));
 		final ObjectId almostEmptyTreeId = new ObjectWriter(db).writeTree(almostEmptyTree);
-		final Commit almostEmptyCommit = new Commit(db);
+		final Commit almostEmptyCommit = new Commit();
 		almostEmptyCommit.setAuthor(new PersonIdent(author, 1154236443000L, -2 * 60)); // not exactly the same
 		almostEmptyCommit.setCommitter(new PersonIdent(author, 1154236443000L, -2 * 60));
 		almostEmptyCommit.setMessage("test022\n");
 		almostEmptyCommit.setTreeId(almostEmptyTreeId);
-		ObjectId almostEmptyCommitId = new ObjectWriter(db).writeCommit(almostEmptyCommit);
+		ObjectId almostEmptyCommitId = insertCommit(almostEmptyCommit);
 		final Tag t = new Tag(db);
 		t.setObjId(almostEmptyCommitId);
 		t.setType("commit");
@@ -511,17 +521,17 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		final Tree almostEmptyTree = new Tree(db);
 		almostEmptyTree.addEntry(new FileTreeEntry(almostEmptyTree, emptyId, "empty".getBytes(), false));
 		final ObjectId almostEmptyTreeId = new ObjectWriter(db).writeTree(almostEmptyTree);
-		Commit commit = new Commit(db);
+		Commit commit = new Commit();
 		commit.setTreeId(almostEmptyTreeId);
 		commit.setAuthor(new PersonIdent("Joe H\u00e4cker","joe@example.com",4294967295000L,60));
 		commit.setCommitter(new PersonIdent("Joe Hacker","joe2@example.com",4294967295000L,60));
 		commit.setEncoding("UTF-8");
 		commit.setMessage("\u00dcbergeeks");
-		ObjectId cid = new ObjectWriter(db).writeCommit(commit);
+		ObjectId cid = insertCommit(commit);
 		assertEquals("4680908112778718f37e686cbebcc912730b3154", cid.name());
-		Commit loadedCommit = db.mapCommit(cid);
-		assertNotSame(loadedCommit, commit);
-		assertEquals(commit.getMessage(), loadedCommit.getMessage());
+
+		RevCommit loadedCommit = parseCommit(cid);
+		assertEquals(commit.getMessage(), loadedCommit.getFullMessage());
 	}
 
 	public void test024_createCommitNonAscii() throws IOException {
@@ -529,13 +539,13 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		final Tree almostEmptyTree = new Tree(db);
 		almostEmptyTree.addEntry(new FileTreeEntry(almostEmptyTree, emptyId, "empty".getBytes(), false));
 		final ObjectId almostEmptyTreeId = new ObjectWriter(db).writeTree(almostEmptyTree);
-		Commit commit = new Commit(db);
+		Commit commit = new Commit();
 		commit.setTreeId(almostEmptyTreeId);
 		commit.setAuthor(new PersonIdent("Joe H\u00e4cker","joe@example.com",4294967295000L,60));
 		commit.setCommitter(new PersonIdent("Joe Hacker","joe2@example.com",4294967295000L,60));
 		commit.setEncoding("ISO-8859-1");
 		commit.setMessage("\u00dcbergeeks");
-		ObjectId cid = new ObjectWriter(db).writeCommit(commit);
+		ObjectId cid = insertCommit(commit);
 		assertEquals("2979b39d385014b33287054b87f77bcb3ecb5ebf", cid.name());
 	}
 
@@ -601,82 +611,82 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		assertEquals(ObjectId.fromString("00b1f73724f493096d1ffa0b0f1f1482dbb8c936"),
 				t.getTreeId());
 
-		final Commit c1 = new Commit(db);
+		final Commit c1 = new Commit();
 		c1.setAuthor(new PersonIdent(author, 1154236443000L, -4 * 60));
 		c1.setCommitter(new PersonIdent(committer, 1154236443000L, -4 * 60));
 		c1.setMessage("A Commit\n");
-		c1.setTree(t);
+		c1.setTreeId(t.getTreeId());
 		assertEquals(t.getTreeId(), c1.getTreeId());
-		c1.commit();
+		insertCommit(c1);
 		final ObjectId cmtid1 = ObjectId.fromString(
 				"803aec4aba175e8ab1d666873c984c0308179099");
 		assertEquals(cmtid1, c1.getCommitId());
 
-		final Commit c2 = new Commit(db);
+		final Commit c2 = new Commit();
 		c2.setAuthor(new PersonIdent(author, 1154236443000L, -4 * 60));
 		c2.setCommitter(new PersonIdent(committer, 1154236443000L, -4 * 60));
 		c2.setMessage("A Commit 2\n");
-		c2.setTree(t);
+		c2.setTreeId(t.getTreeId());
 		assertEquals(t.getTreeId(), c2.getTreeId());
-		c2.setParentIds(new ObjectId[] { c1.getCommitId() } );
-		c2.commit();
+		c2.setParentIds(c1.getCommitId());
+		insertCommit(c2);
 		final ObjectId cmtid2 = ObjectId.fromString(
 				"95d068687c91c5c044fb8c77c5154d5247901553");
 		assertEquals(cmtid2, c2.getCommitId());
 
-		Commit rm2 = db.mapCommit(cmtid2);
+		RevCommit rm2 = parseCommit(cmtid2);
 		assertNotSame(c2, rm2); // assert the parsed objects is not from the cache
-		assertEquals(c2.getAuthor(), rm2.getAuthor());
-		assertEquals(c2.getCommitId(), rm2.getCommitId());
-		assertEquals(c2.getMessage(), rm2.getMessage());
-		assertEquals(c2.getTree().getTreeId(), rm2.getTree().getTreeId());
-		assertEquals(1, rm2.getParentIds().length);
-		assertEquals(c1.getCommitId(), rm2.getParentIds()[0]);
-
-		final Commit c3 = new Commit(db);
+		assertEquals(c2.getAuthor(), rm2.getAuthorIdent());
+		assertEquals(c2.getCommitId(), rm2.getId());
+		assertEquals(c2.getMessage(), rm2.getFullMessage());
+		assertEquals(c2.getTreeId(), rm2.getTree().getId());
+		assertEquals(1, rm2.getParentCount());
+		assertEquals(c1.getCommitId(), rm2.getParent(0));
+
+		final Commit c3 = new Commit();
 		c3.setAuthor(new PersonIdent(author, 1154236443000L, -4 * 60));
 		c3.setCommitter(new PersonIdent(committer, 1154236443000L, -4 * 60));
 		c3.setMessage("A Commit 3\n");
-		c3.setTree(t);
+		c3.setTreeId(t.getTreeId());
 		assertEquals(t.getTreeId(), c3.getTreeId());
-		c3.setParentIds(new ObjectId[] { c1.getCommitId(), c2.getCommitId() });
-		c3.commit();
+		c3.setParentIds(c1.getCommitId(), c2.getCommitId());
+		insertCommit(c3);
 		final ObjectId cmtid3 = ObjectId.fromString(
 				"ce6e1ce48fbeeb15a83f628dc8dc2debefa066f4");
 		assertEquals(cmtid3, c3.getCommitId());
 
-		Commit rm3 = db.mapCommit(cmtid3);
+		RevCommit rm3 = parseCommit(cmtid3);
 		assertNotSame(c3, rm3); // assert the parsed objects is not from the cache
-		assertEquals(c3.getAuthor(), rm3.getAuthor());
-		assertEquals(c3.getCommitId(), rm3.getCommitId());
-		assertEquals(c3.getMessage(), rm3.getMessage());
-		assertEquals(c3.getTree().getTreeId(), rm3.getTree().getTreeId());
-		assertEquals(2, rm3.getParentIds().length);
-		assertEquals(c1.getCommitId(), rm3.getParentIds()[0]);
-		assertEquals(c2.getCommitId(), rm3.getParentIds()[1]);
-
-		final Commit c4 = new Commit(db);
+		assertEquals(c3.getAuthor(), rm3.getAuthorIdent());
+		assertEquals(c3.getCommitId(), rm3.getId());
+		assertEquals(c3.getMessage(), rm3.getFullMessage());
+		assertEquals(c3.getTreeId(), rm3.getTree().getId());
+		assertEquals(2, rm3.getParentCount());
+		assertEquals(c1.getCommitId(), rm3.getParent(0));
+		assertEquals(c2.getCommitId(), rm3.getParent(1));
+
+		final Commit c4 = new Commit();
 		c4.setAuthor(new PersonIdent(author, 1154236443000L, -4 * 60));
 		c4.setCommitter(new PersonIdent(committer, 1154236443000L, -4 * 60));
 		c4.setMessage("A Commit 4\n");
-		c4.setTree(t);
+		c4.setTreeId(t.getTreeId());
 		assertEquals(t.getTreeId(), c3.getTreeId());
-		c4.setParentIds(new ObjectId[] { c1.getCommitId(), c2.getCommitId(), c3.getCommitId() });
-		c4.commit();
+		c4.setParentIds(c1.getCommitId(), c2.getCommitId(), c3.getCommitId());
+		insertCommit(c4);
 		final ObjectId cmtid4 = ObjectId.fromString(
 				"d1fca9fe3fef54e5212eb67902c8ed3e79736e27");
 		assertEquals(cmtid4, c4.getCommitId());
 
-		Commit rm4 = db.mapCommit(cmtid4);
+		RevCommit rm4 = parseCommit(cmtid4);
 		assertNotSame(c4, rm3); // assert the parsed objects is not from the cache
-		assertEquals(c4.getAuthor(), rm4.getAuthor());
-		assertEquals(c4.getCommitId(), rm4.getCommitId());
-		assertEquals(c4.getMessage(), rm4.getMessage());
-		assertEquals(c4.getTree().getTreeId(), rm4.getTree().getTreeId());
-		assertEquals(3, rm4.getParentIds().length);
-		assertEquals(c1.getCommitId(), rm4.getParentIds()[0]);
-		assertEquals(c2.getCommitId(), rm4.getParentIds()[1]);
-		assertEquals(c3.getCommitId(), rm4.getParentIds()[2]);
+		assertEquals(c4.getAuthor(), rm4.getAuthorIdent());
+		assertEquals(c4.getCommitId(), rm4.getId());
+		assertEquals(c4.getMessage(), rm4.getFullMessage());
+		assertEquals(c4.getTreeId(), rm4.getTree().getId());
+		assertEquals(3, rm4.getParentCount());
+		assertEquals(c1.getCommitId(), rm4.getParent(0));
+		assertEquals(c2.getCommitId(), rm4.getParent(1));
+		assertEquals(c3.getCommitId(), rm4.getParent(2));
 	}
 
 	public void test027_UnpackedRefHigherPriorityThanPacked() throws IOException {
@@ -717,13 +727,6 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 		assertEquals(newId2, db.resolve("refs/heads/foobar"));
 	}
 
-	public void test029_mapObject() throws IOException {
-		assertEquals(new byte[0].getClass(), db.mapObject(ObjectId.fromString("5b6e7c66c276e7610d4a73c70ec1a1f7c1003259"), null).getClass());
-		assertEquals(Commit.class, db.mapObject(ObjectId.fromString("540a36d136cf413e4b064c2b0e0a4db60f77feab"), null).getClass());
-		assertEquals(Tree.class, db.mapObject(ObjectId.fromString("aabf2ffaec9b497f0950352b3e582d73035c2035"), null).getClass());
-		assertEquals(Tag.class, db.mapObject(ObjectId.fromString("17768080a2318cd89bba4c8b87834401e2095703"), null).getClass());
-	}
-
 	public void test30_stripWorkDir() {
 		File relCwd = new File(".");
 		File absCwd = relCwd.getAbsoluteFile();
@@ -750,6 +753,30 @@ public class T0003_Basic extends SampleDataRepositoryTestCase {
 
 	}
 
+	private ObjectId insertCommit(final Commit commit) throws IOException,
+			UnsupportedEncodingException {
+		ObjectInserter oi = db.newObjectInserter();
+		try {
+			ObjectId id = oi.insert(Constants.OBJ_COMMIT, oi.format(commit));
+			oi.flush();
+			commit.setCommitId(id);
+			return id;
+		} finally {
+			oi.release();
+		}
+	}
+
+	private RevCommit parseCommit(AnyObjectId id)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		RevWalk rw = new RevWalk(db);
+		try {
+			return rw.parseCommit(id);
+		} finally {
+			rw.release();
+		}
+	}
+
 	/**
 	 * Kick the timestamp of a local file.
 	 * <p>
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java
index ae4b33477..859e92fdb 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java
@@ -162,12 +162,12 @@ public class CommitCommand extends GitCommand<RevCommit> {
 					ObjectId indexTreeId = index.writeTree(odi);
 
 					// Create a Commit object, populate it and write it
-					Commit commit = new Commit(repo);
+					Commit commit = new Commit();
 					commit.setCommitter(committer);
 					commit.setAuthor(author);
 					commit.setMessage(message);
 
-					commit.setParentIds(parents.toArray(new ObjectId[] {}));
+					commit.setParentIds(parents);
 					commit.setTreeId(indexTreeId);
 					ObjectId commitId = odi.insert(Constants.OBJ_COMMIT, odi
 							.format(commit));
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
index 4d37c28e0..a6e648d36 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/api/MergeCommand.java
@@ -57,11 +57,11 @@ import org.eclipse.jgit.lib.GitIndex;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.ObjectIdRef;
 import org.eclipse.jgit.lib.Ref;
-import org.eclipse.jgit.lib.Ref.Storage;
 import org.eclipse.jgit.lib.RefUpdate;
-import org.eclipse.jgit.lib.RefUpdate.Result;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.lib.WorkDirCheckout;
+import org.eclipse.jgit.lib.Ref.Storage;
+import org.eclipse.jgit.lib.RefUpdate.Result;
 import org.eclipse.jgit.merge.MergeStrategy;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
@@ -176,8 +176,8 @@ public class MergeCommand extends GitCommand<MergeResult> {
 		File workDir = repo.getWorkTree();
 		if (workDir != null) {
 			WorkDirCheckout workDirCheckout = new WorkDirCheckout(repo,
-					workDir, headCommit.asCommit(revWalk).getTree(), index,
-					newHeadCommit.asCommit(revWalk).getTree());
+					workDir, repo.mapTree(headCommit.getTree()), index,
+					repo.mapTree(newHeadCommit.getTree()));
 			workDirCheckout.setFailOnConflict(true);
 			try {
 				workDirCheckout.checkout();
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BlobBasedConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BlobBasedConfig.java
index b56966ff4..f25b0781e 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BlobBasedConfig.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BlobBasedConfig.java
@@ -51,15 +51,24 @@ import java.text.MessageFormat;
 
 import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.errors.ConfigInvalidException;
+import org.eclipse.jgit.errors.IncorrectObjectTypeException;
+import org.eclipse.jgit.errors.MissingObjectException;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.revwalk.RevTree;
+import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.treewalk.TreeWalk;
+import org.eclipse.jgit.util.IO;
 import org.eclipse.jgit.util.RawParseUtils;
 
 /**
- * The configuration file based on the blobs stored in the repository
+ * Configuration file based on the blobs stored in the repository.
+ *
+ * This implementation currently only provides reading support, and is primarily
+ * useful for supporting the {@code .gitmodules} file.
  */
 public class BlobBasedConfig extends Config {
 	/**
-	 * The constructor from a byte array
+	 * Parse a configuration from a byte array.
 	 *
 	 * @param base
 	 *            the base configuration file
@@ -75,11 +84,11 @@ public class BlobBasedConfig extends Config {
 	}
 
 	/**
-	 * The constructor from object identifier
+	 * Load a configuration file from a blob.
 	 *
 	 * @param base
 	 *            the base configuration file
-	 * @param r
+	 * @param db
 	 *            the repository
 	 * @param objectId
 	 *            the object identifier
@@ -88,22 +97,50 @@ public class BlobBasedConfig extends Config {
 	 * @throws ConfigInvalidException
 	 *             the blob is not a valid configuration format.
 	 */
-	public BlobBasedConfig(Config base, final Repository r,
-			final ObjectId objectId) throws IOException, ConfigInvalidException {
-		super(base);
-		ObjectLoader loader = r.open(objectId, Constants.OBJ_BLOB);
-		fromText(RawParseUtils.decode(loader.getCachedBytes()));
+	public BlobBasedConfig(Config base, Repository db, AnyObjectId objectId)
+			throws IOException, ConfigInvalidException {
+		this(base, read(db, objectId));
+	}
+
+	private static byte[] read(Repository db, AnyObjectId blobId)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		ObjectReader or = db.newObjectReader();
+		try {
+			return read(or, blobId);
+		} finally {
+			or.release();
+		}
+	}
+
+	private static byte[] read(ObjectReader or, AnyObjectId blobId)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		ObjectLoader loader = or.open(blobId, Constants.OBJ_BLOB);
+		if (loader.isLarge()) {
+			ObjectStream in = loader.openStream();
+			try {
+				byte[] buf = new byte[(int) in.getSize()];
+				IO.readFully(in, buf, 0, buf.length);
+				return buf;
+			} finally {
+				in.close();
+			}
+		}
+		return loader.getCachedBytes();
 	}
 
 	/**
-	 * The constructor from commit and path
+	 * Load a configuration file from a blob stored in a specific commit.
 	 *
 	 * @param base
 	 *            the base configuration file
-	 * @param commit
-	 *            the commit that contains the object
+	 * @param db
+	 *            the repository containing the objects.
+	 * @param treeish
+	 *            the tree (or commit) that contains the object
 	 * @param path
-	 *            the path within the tree of the commit
+	 *            the path within the tree
 	 * @throws FileNotFoundException
 	 *             the path does not exist in the commit's tree.
 	 * @throws IOException
@@ -111,16 +148,37 @@ public class BlobBasedConfig extends Config {
 	 * @throws ConfigInvalidException
 	 *             the blob is not a valid configuration format.
 	 */
-	public BlobBasedConfig(Config base, final Commit commit, final String path)
-			throws FileNotFoundException, IOException, ConfigInvalidException {
-		super(base);
-		final ObjectId treeId = commit.getTreeId();
-		final Repository r = commit.getRepository();
-		final TreeWalk tree = TreeWalk.forPath(r, path, treeId);
-		if (tree == null)
-			throw new FileNotFoundException(MessageFormat.format(JGitText.get().entryNotFoundByPath, path));
-		final ObjectId blobId = tree.getObjectId(0);
-		ObjectLoader loader = r.open(blobId,Constants.OBJ_BLOB);
-		fromText(RawParseUtils.decode(loader.getCachedBytes()));
+	public BlobBasedConfig(Config base, Repository db, AnyObjectId treeish,
+			String path) throws FileNotFoundException, IOException,
+			ConfigInvalidException {
+		this(base, read(db, treeish, path));
+	}
+
+	private static byte[] read(Repository db, AnyObjectId treeish, String path)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		ObjectReader or = db.newObjectReader();
+		try {
+			TreeWalk tree = TreeWalk.forPath(or, path, asTree(or, treeish));
+			if (tree == null)
+				throw new FileNotFoundException(MessageFormat.format(JGitText
+						.get().entryNotFoundByPath, path));
+			return read(or, tree.getObjectId(0));
+		} finally {
+			or.release();
+		}
+	}
+
+	private static AnyObjectId asTree(ObjectReader or, AnyObjectId treeish)
+			throws MissingObjectException, IncorrectObjectTypeException,
+			IOException {
+		if (treeish instanceof RevTree)
+			return treeish;
+
+		if (treeish instanceof RevCommit
+				&& ((RevCommit) treeish).getTree() != null)
+			return ((RevCommit) treeish).getTree();
+
+		return new RevWalk(or).parseTree(treeish).getId();
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Commit.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Commit.java
index eeffb08e9..ebf75f92b 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Commit.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Commit.java
@@ -45,25 +45,19 @@
 
 package org.eclipse.jgit.lib;
 
-import java.io.ByteArrayInputStream;
-import java.io.DataInputStream;
-import java.io.IOException;
 import java.nio.charset.Charset;
-import java.text.MessageFormat;
-
-import org.eclipse.jgit.JGitText;
-import org.eclipse.jgit.errors.CorruptObjectException;
-import org.eclipse.jgit.errors.MissingObjectException;
+import java.util.List;
 
 /**
- * Instances of this class represent a Commit object. It represents a snapshot
- * in a Git repository, who created it and when.
+ * Mutable builder to construct a commit recording the state of a project.
+ *
+ * Applications should use this object when they need to manually construct a
+ * commit and want precise control over its fields. For a higher level interface
+ * see {@link org.eclipse.jgit.api.CommitCommand}.
  */
-public class Commit implements Treeish {
+public class Commit {
 	private static final ObjectId[] EMPTY_OBJECTID_LIST = new ObjectId[0];
 
-	private final Repository objdb;
-
 	private ObjectId commitId;
 
 	private ObjectId treeId;
@@ -76,102 +70,21 @@ public class Commit implements Treeish {
 
 	private String message;
 
-	private Tree treeObj;
-
-	private byte[] raw;
-
 	private Charset encoding;
 
-	/**
-	 * Create an empty commit object. More information must be fed to this
-	 * object to make it useful.
-	 *
-	 * @param db
-	 *            The repository with which to associate it.
-	 */
-	public Commit(final Repository db) {
-		objdb = db;
+	/** Initialize an empty commit. */
+	public Commit() {
 		parentIds = EMPTY_OBJECTID_LIST;
+		encoding = Constants.CHARSET;
 	}
 
-	/**
-	 * Create a commit associated with these parents and associate it with a
-	 * repository.
-	 *
-	 * @param db
-	 *            The repository to which this commit object belongs
-	 * @param parentIds
-	 *            Id's of the parent(s)
-	 */
-	public Commit(final Repository db, final ObjectId[] parentIds) {
-		objdb = db;
-		this.parentIds = parentIds;
-	}
-
-	/**
-	 * Create a commit object with the specified id and data from and existing
-	 * commit object in a repository.
-	 *
-	 * @param db
-	 *            The repository to which this commit object belongs
-	 * @param id
-	 *            Commit id
-	 * @param raw
-	 *            Raw commit object data
-	 */
-	public Commit(final Repository db, final ObjectId id, final byte[] raw) {
-		objdb = db;
-		commitId = id;
-		treeId = ObjectId.fromString(raw, 5);
-		parentIds = new ObjectId[1];
-		int np=0;
-		int rawPtr = 46;
-		for (;;) {
-			if (raw[rawPtr] != 'p')
-				break;
-			if (np == 0) {
-				parentIds[np++] = ObjectId.fromString(raw, rawPtr + 7);
-			} else if (np == 1) {
-				parentIds = new ObjectId[] { parentIds[0], ObjectId.fromString(raw, rawPtr + 7) };
-				np++;
-			} else {
-				if (parentIds.length <= np) {
-					ObjectId[] old = parentIds;
-					parentIds = new ObjectId[parentIds.length+32];
-					for (int i=0; i<np; ++i)
-						parentIds[i] = old[i];
-				}
-				parentIds[np++] = ObjectId.fromString(raw, rawPtr + 7);
-			}
-			rawPtr += 48;
-		}
-		if (np != parentIds.length) {
-			ObjectId[] old = parentIds;
-			parentIds = new ObjectId[np];
-			for (int i=0; i<np; ++i)
-				parentIds[i] = old[i];
-		} else
-			if (np == 0)
-				parentIds = EMPTY_OBJECTID_LIST;
-		this.raw = raw;
-	}
-
-	/**
-	 * @return get repository for the commit
-	 */
-	public Repository getRepository() {
-		return objdb;
-	}
-
-	/**
-	 * @return The commit object id
-	 */
+	/** @return this commit's object id. */
 	public ObjectId getCommitId() {
 		return commitId;
 	}
 
 	/**
-	 * Set the id of this object.
+	 * Set the id of this commit object.
 	 *
 	 * @param id
 	 *            the id that we calculated for this object.
@@ -180,6 +93,7 @@ public class Commit implements Treeish {
 		commitId = id;
 	}
 
+	/** @return id of the root tree listing this commit's snapshot. */
 	public ObjectId getTreeId() {
 		return treeId;
 	}
@@ -188,198 +102,197 @@ public class Commit implements Treeish {
 	 * Set the tree id for this commit object
 	 *
 	 * @param id
+	 *            the tree identity.
 	 */
-	public void setTreeId(final ObjectId id) {
-		if (treeId==null || !treeId.equals(id)) {
-			treeObj = null;
-		}
-		treeId = id;
-	}
-
-	public Tree getTree() throws IOException {
-		if (treeObj == null) {
-			treeObj = objdb.mapTree(getTreeId());
-			if (treeObj == null) {
-				throw new MissingObjectException(getTreeId(),
-						Constants.TYPE_TREE);
-			}
-		}
-		return treeObj;
-	}
-
-	/**
-	 * Set the tree object for this commit
-	 * @see #setTreeId
-	 * @param t the Tree object
-	 */
-	public void setTree(final Tree t) {
-		treeId = t.getTreeId();
-		treeObj = t;
+	public void setTreeId(AnyObjectId id) {
+		treeId = id.copy();
+		commitId = null;
 	}
 
-	/**
-	 * @return the author and authoring time for this commit
-	 */
+	/** @return the author of this commit (who wrote it). */
 	public PersonIdent getAuthor() {
-		decode();
 		return author;
 	}
 
 	/**
-	 * Set the author and authoring time for this commit
-	 * @param a
+	 * Set the author (name, email address, and date) of who wrote the commit.
+	 *
+	 * @param newAuthor
+	 *            the new author. Should not be null.
 	 */
-	public void setAuthor(final PersonIdent a) {
-		author = a;
+	public void setAuthor(PersonIdent newAuthor) {
+		author = newAuthor;
+		commitId = null;
 	}
 
-	/**
-	 * @return the committer and commit time for this object
-	 */
+	/** @return the committer and commit time for this object. */
 	public PersonIdent getCommitter() {
-		decode();
 		return committer;
 	}
 
 	/**
 	 * Set the committer and commit time for this object
-	 * @param c the committer information
+	 *
+	 * @param newCommitter
+	 *            the committer information. Should not be null.
 	 */
-	public void setCommitter(final PersonIdent c) {
-		committer = c;
+	public void setCommitter(PersonIdent newCommitter) {
+		committer = newCommitter;
+		commitId = null;
 	}
 
-	/**
-	 * @return the object ids of this commit
-	 */
+	/** @return the ancestors of this commit. Never null. */
 	public ObjectId[] getParentIds() {
 		return parentIds;
 	}
 
 	/**
-	 * @return the commit message
+	 * Set the parent of this commit.
+	 *
+	 * @param newParent
+	 *            the single parent for the commit.
 	 */
-	public String getMessage() {
-		decode();
-		return message;
+	public void setParentId(AnyObjectId newParent) {
+		parentIds = new ObjectId[] { newParent.copy() };
+		commitId = null;
 	}
 
 	/**
-	 * Set the parents of this commit
-	 * @param parentIds
+	 * Set the parents of this commit.
+	 *
+	 * @param parent1
+	 *            the first parent of this commit. Typically this is the current
+	 *            value of the {@code HEAD} reference and is thus the current
+	 *            branch's position in history.
+	 * @param parent2
+	 *            the second parent of this merge commit. Usually this is the
+	 *            branch being merged into the current branch.
 	 */
-	public void setParentIds(ObjectId[] parentIds) {
-		this.parentIds = new ObjectId[parentIds.length];
-		for (int i=0; i<parentIds.length; ++i)
-			this.parentIds[i] = parentIds[i];
+	public void setParentIds(AnyObjectId parent1, AnyObjectId parent2) {
+		parentIds = new ObjectId[] { parent1.copy(), parent2.copy() };
+		commitId = null;
 	}
 
-	private void decode() {
-		// FIXME: handle I/O errors
-		if (raw != null) {
-			try {
-				DataInputStream br = new DataInputStream(new ByteArrayInputStream(raw));
-				String n = br.readLine();
-				if (n == null || !n.startsWith("tree ")) {
-					throw new CorruptObjectException(commitId, JGitText.get().corruptObjectNotree);
-				}
-				while ((n = br.readLine()) != null && n.startsWith("parent ")) {
-					// empty body
-				}
-				if (n == null || !n.startsWith("author ")) {
-					throw new CorruptObjectException(commitId, JGitText.get().corruptObjectNoAuthor);
-				}
-				String rawAuthor = n.substring("author ".length());
-				n = br.readLine();
-				if (n == null || !n.startsWith("committer ")) {
-					throw new CorruptObjectException(commitId, JGitText.get().corruptObjectNoCommitter);
-				}
-				String rawCommitter = n.substring("committer ".length());
-				n = br.readLine();
-				if (n != null && n.startsWith(	"encoding"))
-					encoding = Charset.forName(n.substring("encoding ".length()));
-				else
-					if (n == null || !n.equals("")) {
-						throw new CorruptObjectException(commitId, MessageFormat.format(
-								JGitText.get().corruptObjectMalformedHeader, n));
-				}
-				byte[] readBuf = new byte[br.available()]; // in-memory stream so this is all bytes left
-				br.read(readBuf);
-				int msgstart = readBuf.length != 0 ? ( readBuf[0] == '\n' ? 1 : 0 ) : 0;
-
-				// If encoding is not specified, the default for commit is UTF-8
-				if (encoding == null) encoding = Constants.CHARSET;
-
-				// TODO: this isn't reliable so we need to guess the encoding from the actual content
-				author = new PersonIdent(new String(rawAuthor.getBytes(),encoding.name()));
-				committer = new PersonIdent(new String(rawCommitter.getBytes(),encoding.name()));
-				message = new String(readBuf,msgstart, readBuf.length-msgstart, encoding.name());
-			} catch (IOException e) {
-				e.printStackTrace();
-			} finally {
-				raw = null;
-			}
-		}
+	/**
+	 * Set the parents of this commit.
+	 *
+	 * @param newParents
+	 *            the entire list of parents for this commit.
+	 */
+	public void setParentIds(ObjectId... newParents) {
+		parentIds = new ObjectId[newParents.length];
+		for (int i = 0; i < newParents.length; i++)
+			parentIds[i] = newParents[i].copy();
+		commitId = null;
 	}
 
 	/**
-	 * Set the commit message
+	 * Set the parents of this commit.
 	 *
-	 * @param m the commit message
+	 * @param newParents
+	 *            the entire list of parents for this commit.
 	 */
-	public void setMessage(final String m) {
-		message = m;
+	public void setParentIds(List<? extends AnyObjectId> newParents) {
+		parentIds = new ObjectId[newParents.size()];
+		for (int i = 0; i < newParents.size(); i++)
+			parentIds[i] = newParents.get(i).copy();
+		commitId = null;
 	}
 
 	/**
-	 * Persist this commit object
+	 * Add a parent onto the end of the parent list.
 	 *
-	 * @throws IOException
+	 * @param additionalParent
+	 *            new parent to add onto the end of the current parent list.
 	 */
-	public void commit() throws IOException {
-		if (getCommitId() != null)
-			throw new IllegalStateException(MessageFormat.format(JGitText.get().commitAlreadyExists, getCommitId()));
-		ObjectInserter odi = objdb.newObjectInserter();
-		try {
-			ObjectId id = odi.insert(Constants.OBJ_COMMIT, odi.format(this));
-			odi.flush();
-			setCommitId(id);
-		} finally {
-			odi.release();
+	public void addParentId(AnyObjectId additionalParent) {
+		if (parentIds.length == 0) {
+			setParentId(additionalParent);
+		} else {
+			ObjectId[] newParents = new ObjectId[parentIds.length + 1];
+			for (int i = 0; i < parentIds.length; i++)
+				newParents[i] = parentIds[i];
+			newParents[parentIds.length] = additionalParent.copy();
+			parentIds = newParents;
+			commitId = null;
 		}
 	}
 
-	public String toString() {
-		return "Commit[" + ObjectId.toString(getCommitId()) + " " + getAuthor() + "]"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
+	/** @return the complete commit message. */
+	public String getMessage() {
+		return message;
 	}
 
 	/**
-	 * State the encoding for the commit information
+	 * Set the commit message.
 	 *
-	 * @param e
-	 *            the encoding. See {@link Charset}
+	 * @param newMessage
+	 *            the commit message. Should not be null.
 	 */
-	public void setEncoding(String e) {
-		encoding = Charset.forName(e);
+	public void setMessage(final String newMessage) {
+		message = newMessage;
 	}
 
 	/**
-	 * State the encoding for the commit information
+	 * Set the encoding for the commit information
 	 *
-	 * @param e
-	 *            the encoding. See {@link Charset}
+	 * @param encodingName
+	 *            the encoding name. See {@link Charset#forName(String)}.
 	 */
-	public void setEncoding(Charset e) {
-		encoding = e;
+	public void setEncoding(String encodingName) {
+		encoding = Charset.forName(encodingName);
 	}
 
 	/**
-	 * @return the encoding used. See {@link Charset}
+	 * Set the encoding for the commit information
+	 *
+	 * @param enc
+	 *            the encoding to use.
 	 */
-	public String getEncoding() {
-		if (encoding != null)
-			return encoding.name();
-		else
-			return null;
+	public void setEncoding(Charset enc) {
+		encoding = enc;
+	}
+
+	/** @return the encoding that should be used for the commit message text. */
+	public Charset getEncoding() {
+		return encoding;
+	}
+
+	@Override
+	public String toString() {
+		StringBuilder r = new StringBuilder();
+		r.append("Commit");
+		if (commitId != null)
+			r.append("[" + commitId.name() + "]");
+		r.append("={\n");
+
+		r.append("tree ");
+		r.append(treeId != null ? treeId.name() : "NOT_SET");
+		r.append("\n");
+
+		for (ObjectId p : parentIds) {
+			r.append("parent ");
+			r.append(p.name());
+			r.append("\n");
+		}
+
+		r.append("author ");
+		r.append(author != null ? author.toString() : "NOT_SET");
+		r.append("\n");
+
+		r.append("committer ");
+		r.append(committer != null ? committer.toString() : "NOT_SET");
+		r.append("\n");
+
+		if (encoding != null && encoding != Constants.CHARSET) {
+			r.append("encoding ");
+			r.append(encoding.name());
+			r.append("\n");
+		}
+
+		r.append("\n");
+		r.append(message != null ? message : "");
+		r.append("}");
+		return r.toString();
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectInserter.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectInserter.java
index a9522452b..349b8197d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectInserter.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectInserter.java
@@ -53,6 +53,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStreamWriter;
 import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
 import java.security.MessageDigest;
 import java.text.MessageFormat;
 
@@ -304,10 +305,7 @@ public abstract class ObjectInserter {
 	 */
 	public final byte[] format(Commit commit)
 			throws UnsupportedEncodingException {
-		String encoding = commit.getEncoding();
-		if (encoding == null)
-			encoding = Constants.CHARACTER_ENCODING;
-
+		Charset encoding = commit.getEncoding();
 		ByteArrayOutputStream os = new ByteArrayOutputStream();
 		OutputStreamWriter w = new OutputStreamWriter(os, encoding);
 		try {
@@ -316,11 +314,10 @@ public abstract class ObjectInserter {
 			commit.getTreeId().copyTo(os);
 			os.write('\n');
 
-			ObjectId[] ps = commit.getParentIds();
-			for (int i = 0; i < ps.length; ++i) {
+			for (ObjectId p : commit.getParentIds()) {
 				os.write(hparent);
 				os.write(' ');
-				ps[i].copyTo(os);
+				p.copyTo(os);
 				os.write('\n');
 			}
 
@@ -336,16 +333,19 @@ public abstract class ObjectInserter {
 			w.flush();
 			os.write('\n');
 
-			if (!encoding.equals(Constants.CHARACTER_ENCODING)) {
+			if (encoding != Constants.CHARSET) {
 				os.write(hencoding);
 				os.write(' ');
-				os.write(Constants.encodeASCII(encoding));
+				os.write(Constants.encodeASCII(encoding.name()));
 				os.write('\n');
 			}
 
 			os.write('\n');
-			w.write(commit.getMessage());
-			w.flush();
+
+			if (commit.getMessage() != null) {
+				w.write(commit.getMessage());
+				w.flush();
+			}
 		} catch (IOException err) {
 			// This should never occur, the only way to get it above is
 			// for the ByteArrayOutputStream to throw, but it doesn't.
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
index 27fdf6841..6059efde9 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Repository.java
@@ -270,84 +270,6 @@ public abstract class Repository {
 		return getObjectDatabase().open(objectId, typeHint);
 	}
 
-	/**
-	 * Access a Commit object using a symbolic reference. This reference may
-	 * be a SHA-1 or ref in combination with a number of symbols translating
-	 * from one ref or SHA1-1 to another, such as HEAD^ etc.
-	 *
-	 * @param revstr a reference to a git commit object
-	 * @return a Commit named by the specified string
-	 * @throws IOException for I/O error or unexpected object type.
-	 *
-	 * @see #resolve(String)
-	 * @deprecated Use {@link #resolve(String)} and pass its return value to
-	 * {@link org.eclipse.jgit.revwalk.RevWalk#parseCommit(AnyObjectId)}.
-	 */
-	@Deprecated
-	public Commit mapCommit(final String revstr) throws IOException {
-		final ObjectId id = resolve(revstr);
-		return id != null ? mapCommit(id) : null;
-	}
-
-	/**
-	 * Access any type of Git object by id and
-	 *
-	 * @param id
-	 *            SHA-1 of object to read
-	 * @param refName optional, only relevant for simple tags
-	 * @return The Git object if found or null
-	 * @throws IOException
-	 * @deprecated Use {@link org.eclipse.jgit.revwalk.RevWalk#parseCommit(AnyObjectId)},
-	 *  or {@link org.eclipse.jgit.revwalk.RevWalk#parseTag(AnyObjectId)}.
-	 *  To read a tree, use {@link org.eclipse.jgit.treewalk.TreeWalk#addTree(AnyObjectId)}.
-	 *  To read a blob, open it with {@link #open(AnyObjectId)}.
-	 */
-	@Deprecated
-	public Object mapObject(final ObjectId id, final String refName) throws IOException {
-		final ObjectLoader or;
-		try {
-			or = open(id);
-		} catch (MissingObjectException notFound) {
-			return null;
-		}
-		final byte[] raw = or.getCachedBytes();
-		switch (or.getType()) {
-		case Constants.OBJ_TREE:
-			return new Tree(this, id, raw);
-
-		case Constants.OBJ_COMMIT:
-			return new Commit(this, id, raw);
-
-		case Constants.OBJ_TAG:
-			return new Tag(this, id, refName, raw);
-
-		case Constants.OBJ_BLOB:
-			return raw;
-
-		default:
-			throw new IncorrectObjectTypeException(id,
-				JGitText.get().incorrectObjectType_COMMITnorTREEnorBLOBnorTAG);
-		}
-	}
-
-	/**
-	 * Access a Commit by SHA'1 id.
-	 * @param id
-	 * @return Commit or null
-	 * @throws IOException for I/O error or unexpected object type.
-	 * @deprecated Use {@link org.eclipse.jgit.revwalk.RevWalk#parseCommit(AnyObjectId)}.
-	 */
-	@Deprecated
-	public Commit mapCommit(final ObjectId id) throws IOException {
-		final ObjectLoader or;
-		try {
-			or = open(id, Constants.OBJ_COMMIT);
-		} catch (MissingObjectException notFound) {
-			return null;
-		}
-		return new Commit(this, id, or.getCachedBytes());
-	}
-
 	/**
 	 * Access a Tree object using a symbolic reference. This reference may
 	 * be a SHA-1 or ref in combination with a number of symbols translating
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
index 84cc704c3..74a51c8a4 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/revwalk/RevCommit.java
@@ -53,7 +53,6 @@ import java.util.List;
 import org.eclipse.jgit.errors.IncorrectObjectTypeException;
 import org.eclipse.jgit.errors.MissingObjectException;
 import org.eclipse.jgit.lib.AnyObjectId;
-import org.eclipse.jgit.lib.Commit;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.MutableObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
@@ -206,18 +205,6 @@ public class RevCommit extends RevObject {
 		return commitTime;
 	}
 
-	/**
-	 * Parse this commit buffer for display.
-	 *
-	 * @param walk
-	 *            revision walker owning this reference.
-	 * @return parsed commit.
-	 */
-	public final Commit asCommit(final RevWalk walk) {
-		// TODO(spearce) Remove repository when this method dies.
-		return new Commit(walk.repository, this, buffer);
-	}
-
 	/**
 	 * Get a reference to this commit's tree.
 	 *