From 7790fd160c4cf011d40d69e0245fe8b56a689911 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sat, 1 Feb 2025 13:36:21 -0800
Subject: [PATCH 01/24] make checkpoint post commit

---
 .../examples/CreateTableAndInsertData.java    |  7 +++---
 .../io/delta/kernel/PostCommitAction.java     | 24 +++++++++++++++++++
 .../delta/kernel/TransactionCommitResult.java | 18 +++++---------
 .../kernel/internal/TransactionImpl.java      | 18 +++++++++++++-
 .../defaults/DeltaTableWriteSuiteBase.scala   | 24 ++++++++++++++-----
 5 files changed, 69 insertions(+), 22 deletions(-)
 create mode 100644 kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index 8328900056a..83685116a43 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -409,10 +409,11 @@ public void insertWithOptionalCheckpoint(String tablePath) throws IOException {
         // for every 10 versions.
         for (int i = 0; i < 12; i++) {
             TransactionCommitResult commitResult = insertDataIntoUnpartitionedTable(tablePath);
-            if (commitResult.isReadyForCheckpoint()) {
+            for(PostCommitAction action: commitResult.getPostCommitActions())
+            if (action.getType().equals("checkpoint")) {
                 // Checkpoint the table
-                Table.forPath(engine, tablePath).checkpoint(engine, commitResult.getVersion());
-                didCheckpoint = true;
+               action.threadSafeInvoke();
+               didCheckpoint = true;
             }
         }
 
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
new file mode 100644
index 00000000000..a3026d6af59
--- /dev/null
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright (2025) The Delta Lake Project Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.delta.kernel;
+
+public interface PostCommitAction {
+
+  void threadSafeInvoke() throws Exception;
+
+  String getType();
+}
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 831fa18245c..149a7fa26af 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -18,6 +18,7 @@
 import io.delta.kernel.annotation.Evolving;
 import io.delta.kernel.engine.Engine;
 import io.delta.kernel.utils.CloseableIterable;
+import java.util.List;
 
 /**
  * Contains the result of a successful transaction commit. Returned by {@link
@@ -28,11 +29,11 @@
 @Evolving
 public class TransactionCommitResult {
   private final long version;
-  private final boolean isReadyForCheckpoint;
+  private final List<PostCommitAction> postCommitActions;
 
-  public TransactionCommitResult(long version, boolean isReadyForCheckpoint) {
+  public TransactionCommitResult(long version, List<PostCommitAction> postCommitActions) {
     this.version = version;
-    this.isReadyForCheckpoint = isReadyForCheckpoint;
+    this.postCommitActions = postCommitActions;
   }
 
   /**
@@ -44,14 +45,7 @@ public long getVersion() {
     return version;
   }
 
-  /**
-   * Is the table ready for checkpoint (i.e. there are enough commits since the last checkpoint)? If
-   * yes the connector can choose to checkpoint as the version the transaction is committed as using
-   * {@link Table#checkpoint(Engine, long)}
-   *
-   * @return Is the table ready for checkpointing?
-   */
-  public boolean isReadyForCheckpoint() {
-    return isReadyForCheckpoint;
+  public List<PostCommitAction> getPostCommitActions() {
+    return postCommitActions;
   }
 }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
index 44b0b49ccd9..ea35b8c08a4 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
@@ -354,7 +354,23 @@ private TransactionCommitResult doCommit(
           "Write file actions to JSON log file `%s`",
           FileNames.deltaFile(logPath, commitAsVersion));
 
-      return new TransactionCommitResult(commitAsVersion, isReadyForCheckpoint(commitAsVersion));
+      List<PostCommitAction> postCommitActions = new ArrayList<>();
+      if (isReadyForCheckpoint(commitAsVersion)) {
+        postCommitActions.add(
+            new PostCommitAction() {
+              @Override
+              public void threadSafeInvoke() throws IOException {
+                Table.forPath(engine, dataPath.toString()).checkpoint(engine, commitAsVersion);
+              }
+
+              @Override
+              public String getType() {
+                return "checkpoint";
+              }
+            });
+      }
+
+      return new TransactionCommitResult(commitAsVersion, postCommitActions);
     } catch (FileAlreadyExistsException e) {
       throw e;
     } catch (IOException ioe) {
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
index 6abef53db27..5957f0b2744 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
@@ -26,8 +26,16 @@ import io.delta.kernel.internal.util.FileNames
 import io.delta.kernel.internal.util.Utils.singletonCloseableIterator
 import io.delta.kernel.internal.{SnapshotImpl, TableConfig, TableImpl}
 import io.delta.kernel.utils.FileStatus
-import io.delta.kernel.{Meta, Operation, Table, Transaction, TransactionBuilder, TransactionCommitResult}
-import io.delta.kernel.data.{ColumnarBatch, ColumnVector, FilteredColumnarBatch, Row}
+import io.delta.kernel.{
+  Meta,
+  Operation,
+  PostCommitAction,
+  Table,
+  Transaction,
+  TransactionBuilder,
+  TransactionCommitResult
+}
+import io.delta.kernel.data.{ColumnVector, ColumnarBatch, FilteredColumnarBatch, Row}
 import io.delta.kernel.defaults.internal.data.DefaultColumnarBatch
 import io.delta.kernel.expressions.Literal
 import io.delta.kernel.expressions.Literal.ofInt
@@ -139,10 +147,14 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     tablePath: String,
     result: TransactionCommitResult,
     expSize: Long): Unit = {
-    if (result.isReadyForCheckpoint) {
-      Table.forPath(engine, tablePath).checkpoint(engine, result.getVersion)
-      verifyLastCheckpointMetadata(tablePath, checkpointAt = result.getVersion, expSize)
-    }
+    result.getPostCommitActions.forEach(
+      action => {
+        if (action.getType == "checkpoint") {
+          action.threadSafeInvoke()
+          verifyLastCheckpointMetadata(tablePath, checkpointAt = result.getVersion, expSize)
+        }
+      }
+    )
   }
 
   /**

From 0fc403dd2f65c11010764f64d67478a36583aa32 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sat, 1 Feb 2025 14:00:55 -0800
Subject: [PATCH 02/24] post commit action

---
 .../io/delta/kernel/PostCommitAction.java     |  4 +++-
 .../defaults/DeltaTableWriteSuiteBase.scala   |  8 +++++--
 .../defaults/DeltaTableWritesSuite.scala      | 21 ++++++++++++++++---
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
index a3026d6af59..1047746cf09 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
@@ -16,9 +16,11 @@
 
 package io.delta.kernel;
 
+import java.io.IOException;
+
 public interface PostCommitAction {
 
-  void threadSafeInvoke() throws Exception;
+  void threadSafeInvoke() throws IOException;
 
   String getType();
 }
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
index 5957f0b2744..214e60ab83f 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
@@ -29,7 +29,6 @@ import io.delta.kernel.utils.FileStatus
 import io.delta.kernel.{
   Meta,
   Operation,
-  PostCommitAction,
   Table,
   Transaction,
   TransactionBuilder,
@@ -411,7 +410,12 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     expVersion: Long,
     expIsReadyForCheckpoint: Boolean): Unit = {
     assert(result.getVersion === expVersion)
-    assert(result.isReadyForCheckpoint === expIsReadyForCheckpoint)
+    assert(
+      result.getPostCommitActions
+        .stream()
+        .filter(action => action.getType == "checkpoint")
+        .count() == 1 === expIsReadyForCheckpoint
+    )
   }
 
   def verifyTableProperties(
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index 83b77ef208b..c8accb6aa11 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -131,7 +131,12 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(!txnResult.isReadyForCheckpoint)
+      assert(
+          txnResult.getPostCommitActions
+            .stream()
+            .filter(action => action.getType == "checkpoint")
+            .count() == 0
+        )
 
       verifyCommitInfo(tablePath = tablePath, version = 0)
       verifyWrittenContent(tablePath, testSchema, Seq.empty)
@@ -350,7 +355,12 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(!txnResult.isReadyForCheckpoint)
+        assert(
+          txnResult.getPostCommitActions
+            .stream()
+            .filter(action => action.getType == "checkpoint")
+            .count() == 0
+        )
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))
       verifyWrittenContent(tablePath, schema, Seq.empty)
@@ -368,7 +378,12 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(!txnResult.isReadyForCheckpoint)
+        assert(
+          txnResult.getPostCommitActions
+            .stream()
+            .filter(action => action.getType == "checkpoint")
+            .count() == 0
+      )
 
       verifyCommitInfo(tablePath, version = 0)
       verifyWrittenContent(tablePath, schema, Seq.empty)

From 9278d0bfccf94cd32ba3e02e1de388d9866ddd3e Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:09:15 -0800
Subject: [PATCH 03/24] use async example

---
 .../kernel/examples/CreateTableAndInsertData.java  | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index 83685116a43..df1e71ad208 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -410,11 +410,17 @@ public void insertWithOptionalCheckpoint(String tablePath) throws IOException {
         for (int i = 0; i < 12; i++) {
             TransactionCommitResult commitResult = insertDataIntoUnpartitionedTable(tablePath);
             for(PostCommitAction action: commitResult.getPostCommitActions())
-            if (action.getType().equals("checkpoint")) {
                 // Checkpoint the table
-               action.threadSafeInvoke();
-               didCheckpoint = true;
-            }
+                didCheckpoint = didCheckpoint || CompletableFuture.supplyAsync(() -> {
+                            // run the code async
+                            try{
+                                action.threadSafeInvoke();
+                            } catch (IOException e) {
+                                return false;
+                            }
+                            return action.getType().equals("checkpoint");
+                        }
+                ).join(); // wait async finish.
         }
 
         if (!didCheckpoint) {

From 396e9022ae34f9b40d4fb8824d7c71f64f1342a9 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:10:16 -0800
Subject: [PATCH 04/24] fix ident

---
 .../examples/CreateTableAndInsertData.java      | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index df1e71ad208..eb093855219 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -412,15 +412,14 @@ public void insertWithOptionalCheckpoint(String tablePath) throws IOException {
             for(PostCommitAction action: commitResult.getPostCommitActions())
                 // Checkpoint the table
                 didCheckpoint = didCheckpoint || CompletableFuture.supplyAsync(() -> {
-                            // run the code async
-                            try{
-                                action.threadSafeInvoke();
-                            } catch (IOException e) {
-                                return false;
-                            }
-                            return action.getType().equals("checkpoint");
-                        }
-                ).join(); // wait async finish.
+                    // run the code async
+                    try{
+                        action.threadSafeInvoke();
+                    } catch (IOException e) {
+                        return false;
+                    }
+                    return action.getType().equals("checkpoint");
+                }).join(); // wait async finish.
         }
 
         if (!didCheckpoint) {

From e18b792087a099f673fd9217e8a189aba32bb1b4 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:24:35 -0800
Subject: [PATCH 05/24] add example for writing async

---
 .../examples/CreateTableAndInsertData.java    |  3 ++-
 .../io/delta/kernel/PostCommitAction.java     |  3 ++-
 .../io/delta/kernel/PostCommitActionType.java | 20 ++++++++++++++
 .../kernel/internal/TransactionImpl.java      | 27 ++++++++++---------
 .../defaults/DeltaTableWriteSuiteBase.scala   |  8 +++---
 .../defaults/DeltaTableWritesSuite.scala      | 19 +++++++------
 6 files changed, 53 insertions(+), 27 deletions(-)
 create mode 100644 kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index eb093855219..c84542fc246 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -17,6 +17,7 @@
 
 import java.io.IOException;
 import java.util.*;
+import java.util.concurrent.CompletableFuture;
 
 import org.apache.commons.cli.Options;
 
@@ -418,7 +419,7 @@ public void insertWithOptionalCheckpoint(String tablePath) throws IOException {
                     } catch (IOException e) {
                         return false;
                     }
-                    return action.getType().equals("checkpoint");
+                    return action.getType().equals(PostCommitActionType.CHECKPOINT);
                 }).join(); // wait async finish.
         }
 
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
index 1047746cf09..a7fc2100c28 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
@@ -20,7 +20,8 @@
 
 public interface PostCommitAction {
 
+  // Invokes the post commit action, implementation of action should be thread safe.
   void threadSafeInvoke() throws IOException;
 
-  String getType();
+  PostCommitActionType getType();
 }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java
new file mode 100644
index 00000000000..85b749dc639
--- /dev/null
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java
@@ -0,0 +1,20 @@
+/*
+ * Copyright (2025) The Delta Lake Project Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.delta.kernel;
+
+public enum PostCommitActionType {
+  CHECKPOINT
+}
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
index ea35b8c08a4..00615b30488 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
@@ -356,18 +356,7 @@ private TransactionCommitResult doCommit(
 
       List<PostCommitAction> postCommitActions = new ArrayList<>();
       if (isReadyForCheckpoint(commitAsVersion)) {
-        postCommitActions.add(
-            new PostCommitAction() {
-              @Override
-              public void threadSafeInvoke() throws IOException {
-                Table.forPath(engine, dataPath.toString()).checkpoint(engine, commitAsVersion);
-              }
-
-              @Override
-              public String getType() {
-                return "checkpoint";
-              }
-            });
+        postCommitActions.add(checkpoint(engine, dataPath.toString(), commitAsVersion));
       }
 
       return new TransactionCommitResult(commitAsVersion, postCommitActions);
@@ -384,6 +373,20 @@ public boolean isBlindAppend() {
     return true;
   }
 
+  private static PostCommitAction checkpoint(Engine engine, String tablePath, long version) {
+    return new PostCommitAction() {
+      @Override
+      public void threadSafeInvoke() throws IOException {
+        Table.forPath(engine, tablePath).checkpoint(engine, version);
+      }
+
+      @Override
+      public PostCommitActionType getType() {
+        return PostCommitActionType.CHECKPOINT;
+      }
+    };
+  }
+
   /**
    * Generates a timestamp which is greater than the commit timestamp of the readSnapshot. This can
    * result in an additional file read and that this will only happen if ICT is enabled.
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
index 214e60ab83f..26fe5df9f17 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
@@ -29,6 +29,7 @@ import io.delta.kernel.utils.FileStatus
 import io.delta.kernel.{
   Meta,
   Operation,
+  PostCommitActionType,
   Table,
   Transaction,
   TransactionBuilder,
@@ -148,7 +149,7 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     expSize: Long): Unit = {
     result.getPostCommitActions.forEach(
       action => {
-        if (action.getType == "checkpoint") {
+        if (action.getType == PostCommitActionType.CHECKPOINT) {
           action.threadSafeInvoke()
           verifyLastCheckpointMetadata(tablePath, checkpointAt = result.getVersion, expSize)
         }
@@ -413,8 +414,9 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     assert(
       result.getPostCommitActions
         .stream()
-        .filter(action => action.getType == "checkpoint")
-        .count() == 1 === expIsReadyForCheckpoint
+        .anyMatch(
+          action => action.getType == PostCommitActionType.CHECKPOINT
+        ) === expIsReadyForCheckpoint
     )
   }
 
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index c8accb6aa11..606210a22fa 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -132,10 +132,10 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
       assert(
-          txnResult.getPostCommitActions
-            .stream()
-            .filter(action => action.getType == "checkpoint")
-            .count() == 0
+        !txnResult.getPostCommitActions.stream()
+          .anyMatch(
+            action => action.getType == PostCommitActionType.CHECKPOINT
+          )
         )
 
       verifyCommitInfo(tablePath = tablePath, version = 0)
@@ -358,8 +358,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
         assert(
           txnResult.getPostCommitActions
             .stream()
-            .filter(action => action.getType == "checkpoint")
-            .count() == 0
+            .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
         )
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))
@@ -379,10 +378,10 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
         assert(
-          txnResult.getPostCommitActions
-            .stream()
-            .filter(action => action.getType == "checkpoint")
-            .count() == 0
+          txnResult.getPostCommitActions.stream()
+          .anyMatch(
+            action => action.getType == PostCommitActionType.CHECKPOINT
+          )
       )
 
       verifyCommitInfo(tablePath, version = 0)

From 8f75f46ffc91a9a201d81b7b935cd9a38af128bf Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:26:18 -0800
Subject: [PATCH 06/24] fix test

---
 .../delta/kernel/defaults/DeltaTableWritesSuite.scala | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index 606210a22fa..5363680aba2 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -356,7 +356,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
         assert(
-          txnResult.getPostCommitActions
+          !txnResult.getPostCommitActions
             .stream()
             .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
         )
@@ -377,11 +377,10 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-        assert(
-          txnResult.getPostCommitActions.stream()
-          .anyMatch(
-            action => action.getType == PostCommitActionType.CHECKPOINT
-          )
+      assert(
+          !txnResult.getPostCommitActions
+            .stream()
+            .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
       )
 
       verifyCommitInfo(tablePath, version = 0)

From debd1ae12962f010b6c463b0f956373500937483 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:27:59 -0800
Subject: [PATCH 07/24] add doc

---
 .../src/main/java/io/delta/kernel/TransactionCommitResult.java | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 149a7fa26af..4fd303d96a5 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -45,6 +45,9 @@ public long getVersion() {
     return version;
   }
 
+  /**
+   * @return list of actions to trigger after commit.
+   */
   public List<PostCommitAction> getPostCommitActions() {
     return postCommitActions;
   }

From c1cbc4751c28880dca3bad798c1b3b0b96172434 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:29:57 -0800
Subject: [PATCH 08/24] fix ident

---
 .../io/delta/kernel/defaults/DeltaTableWritesSuite.scala    | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index 5363680aba2..fd696f0a521 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -355,10 +355,10 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-        assert(
+      assert(
           !txnResult.getPostCommitActions
-            .stream()
-            .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
+          .stream()
+          .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
         )
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))

From f262fe0b4855ad199ac9d0309c0c19a8780db3c3 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Sun, 2 Feb 2025 18:36:03 -0800
Subject: [PATCH 09/24] fix java format

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java    | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 4fd303d96a5..6fd36fdfcf9 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -45,9 +45,7 @@ public long getVersion() {
     return version;
   }
 
-  /**
-   * @return list of actions to trigger after commit.
-   */
+  /** @return list of actions to trigger after commit. */
   public List<PostCommitAction> getPostCommitActions() {
     return postCommitActions;
   }

From 4d5ed9c7b01e36717c31068f0ebe096d45fea329 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Mon, 3 Feb 2025 17:39:31 -0800
Subject: [PATCH 10/24] seperate commit action to hook package

---
 .../examples/CreateTableAndInsertData.java    |  7 ++--
 .../delta/kernel/TransactionCommitResult.java | 11 ++---
 .../io/delta/kernel/hook/CheckpointHook.java  | 42 +++++++++++++++++++
 .../PostCommitHook.java}                      | 11 ++---
 .../PostCommitHookType.java}                  |  4 +-
 .../kernel/internal/TransactionImpl.java      | 22 +++-------
 .../defaults/DeltaTableWriteSuiteBase.scala   | 14 +++----
 .../defaults/DeltaTableWritesSuite.scala      | 13 +++---
 8 files changed, 79 insertions(+), 45 deletions(-)
 create mode 100644 kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java
 rename kernel/kernel-api/src/main/java/io/delta/kernel/{PostCommitAction.java => hook/PostCommitHook.java} (70%)
 rename kernel/kernel-api/src/main/java/io/delta/kernel/{PostCommitActionType.java => hook/PostCommitHookType.java} (90%)

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index c84542fc246..96cf454dc00 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -25,6 +25,7 @@
 import io.delta.kernel.data.FilteredColumnarBatch;
 import io.delta.kernel.data.Row;
 import io.delta.kernel.expressions.Literal;
+import io.delta.kernel.hook.*;
 import io.delta.kernel.utils.*;
 import static io.delta.kernel.examples.utils.Utils.parseArgs;
 
@@ -410,16 +411,16 @@ public void insertWithOptionalCheckpoint(String tablePath) throws IOException {
         // for every 10 versions.
         for (int i = 0; i < 12; i++) {
             TransactionCommitResult commitResult = insertDataIntoUnpartitionedTable(tablePath);
-            for(PostCommitAction action: commitResult.getPostCommitActions())
+            for(PostCommitHook hook: commitResult.getPostCommitHooks())
                 // Checkpoint the table
                 didCheckpoint = didCheckpoint || CompletableFuture.supplyAsync(() -> {
                     // run the code async
                     try{
-                        action.threadSafeInvoke();
+                        hook.threadSafeInvoke(engine);
                     } catch (IOException e) {
                         return false;
                     }
-                    return action.getType().equals(PostCommitActionType.CHECKPOINT);
+                    return hook.getType().equals(PostCommitHookType.CHECKPOINT);
                 }).join(); // wait async finish.
         }
 
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 6fd36fdfcf9..44d8eeaad19 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -17,6 +17,7 @@
 
 import io.delta.kernel.annotation.Evolving;
 import io.delta.kernel.engine.Engine;
+import io.delta.kernel.hook.PostCommitHook;
 import io.delta.kernel.utils.CloseableIterable;
 import java.util.List;
 
@@ -29,11 +30,11 @@
 @Evolving
 public class TransactionCommitResult {
   private final long version;
-  private final List<PostCommitAction> postCommitActions;
+  private final List<PostCommitHook> postCommitHooks;
 
-  public TransactionCommitResult(long version, List<PostCommitAction> postCommitActions) {
+  public TransactionCommitResult(long version, List<PostCommitHook> postCommitHooks) {
     this.version = version;
-    this.postCommitActions = postCommitActions;
+    this.postCommitHooks = postCommitHooks;
   }
 
   /**
@@ -46,7 +47,7 @@ public long getVersion() {
   }
 
   /** @return list of actions to trigger after commit. */
-  public List<PostCommitAction> getPostCommitActions() {
-    return postCommitActions;
+  public List<PostCommitHook> getPostCommitHooks() {
+    return postCommitHooks;
   }
 }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java
new file mode 100644
index 00000000000..1ea9a46cb35
--- /dev/null
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright (2025) The Delta Lake Project Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.delta.kernel.hook;
+
+import io.delta.kernel.Table;
+import io.delta.kernel.engine.Engine;
+import io.delta.kernel.internal.fs.Path;
+import java.io.IOException;
+
+public class CheckpointHook implements PostCommitHook {
+
+  private final Path tablePath;
+  private final long checkpointVersion;
+
+  public CheckpointHook(Path tablePath, long checkpointVersion) {
+    this.tablePath = tablePath;
+    this.checkpointVersion = checkpointVersion;
+  }
+
+  @Override
+  public void threadSafeInvoke(Engine engine) throws IOException {
+    Table.forPath(engine, tablePath.toString()).checkpoint(engine, checkpointVersion);
+  }
+
+  @Override
+  public PostCommitHookType getType() {
+    return PostCommitHookType.CHECKPOINT;
+  }
+}
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
similarity index 70%
rename from kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
rename to kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index a7fc2100c28..571cb503645 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitAction.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -14,14 +14,15 @@
  * limitations under the License.
  */
 
-package io.delta.kernel;
+package io.delta.kernel.hook;
 
+import io.delta.kernel.engine.Engine;
 import java.io.IOException;
 
-public interface PostCommitAction {
+public interface PostCommitHook {
 
-  // Invokes the post commit action, implementation of action should be thread safe.
-  void threadSafeInvoke() throws IOException;
+  /** Invokes the post commit hook, implementation should be thread safe. */
+  void threadSafeInvoke(Engine engine) throws IOException;
 
-  PostCommitActionType getType();
+  PostCommitHookType getType();
 }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
similarity index 90%
rename from kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java
rename to kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
index 85b749dc639..749c5efdcc7 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/PostCommitActionType.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
@@ -13,8 +13,8 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.delta.kernel;
+package io.delta.kernel.hook;
 
-public enum PostCommitActionType {
+public enum PostCommitHookType {
   CHECKPOINT
 }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
index 00615b30488..60467f711d1 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
@@ -27,6 +27,8 @@
 import io.delta.kernel.engine.Engine;
 import io.delta.kernel.exceptions.ConcurrentWriteException;
 import io.delta.kernel.expressions.Column;
+import io.delta.kernel.hook.CheckpointHook;
+import io.delta.kernel.hook.PostCommitHook;
 import io.delta.kernel.internal.actions.*;
 import io.delta.kernel.internal.data.TransactionStateRow;
 import io.delta.kernel.internal.fs.Path;
@@ -354,12 +356,12 @@ private TransactionCommitResult doCommit(
           "Write file actions to JSON log file `%s`",
           FileNames.deltaFile(logPath, commitAsVersion));
 
-      List<PostCommitAction> postCommitActions = new ArrayList<>();
+      List<PostCommitHook> postCommitHooks = new ArrayList<>();
       if (isReadyForCheckpoint(commitAsVersion)) {
-        postCommitActions.add(checkpoint(engine, dataPath.toString(), commitAsVersion));
+        postCommitHooks.add(new CheckpointHook(dataPath, commitAsVersion));
       }
 
-      return new TransactionCommitResult(commitAsVersion, postCommitActions);
+      return new TransactionCommitResult(commitAsVersion, postCommitHooks);
     } catch (FileAlreadyExistsException e) {
       throw e;
     } catch (IOException ioe) {
@@ -373,20 +375,6 @@ public boolean isBlindAppend() {
     return true;
   }
 
-  private static PostCommitAction checkpoint(Engine engine, String tablePath, long version) {
-    return new PostCommitAction() {
-      @Override
-      public void threadSafeInvoke() throws IOException {
-        Table.forPath(engine, tablePath).checkpoint(engine, version);
-      }
-
-      @Override
-      public PostCommitActionType getType() {
-        return PostCommitActionType.CHECKPOINT;
-      }
-    };
-  }
-
   /**
    * Generates a timestamp which is greater than the commit timestamp of the readSnapshot. This can
    * result in an additional file read and that this will only happen if ICT is enabled.
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
index 26fe5df9f17..be01cc2f4d3 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
@@ -29,7 +29,6 @@ import io.delta.kernel.utils.FileStatus
 import io.delta.kernel.{
   Meta,
   Operation,
-  PostCommitActionType,
   Table,
   Transaction,
   TransactionBuilder,
@@ -47,6 +46,7 @@ import io.delta.kernel.types.StructType
 import io.delta.kernel.utils.CloseableIterable.{emptyIterable, inMemoryIterable}
 import io.delta.kernel.utils.CloseableIterator
 import io.delta.kernel.Operation.CREATE_TABLE
+import io.delta.kernel.hook.PostCommitHookType
 import org.apache.commons.io.FileUtils
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.Path
@@ -147,10 +147,10 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     tablePath: String,
     result: TransactionCommitResult,
     expSize: Long): Unit = {
-    result.getPostCommitActions.forEach(
-      action => {
-        if (action.getType == PostCommitActionType.CHECKPOINT) {
-          action.threadSafeInvoke()
+    result.getPostCommitHooks.forEach(
+      hook => {
+        if (hook.getType == PostCommitHookType.CHECKPOINT) {
+          hook.threadSafeInvoke(engine)
           verifyLastCheckpointMetadata(tablePath, checkpointAt = result.getVersion, expSize)
         }
       }
@@ -412,10 +412,10 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     expIsReadyForCheckpoint: Boolean): Unit = {
     assert(result.getVersion === expVersion)
     assert(
-      result.getPostCommitActions
+      result.getPostCommitHooks
         .stream()
         .anyMatch(
-          action => action.getType == PostCommitActionType.CHECKPOINT
+          hook => hook.getType == PostCommitHookType.CHECKPOINT
         ) === expIsReadyForCheckpoint
     )
   }
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index fd696f0a521..f85585adfe3 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -25,6 +25,7 @@ import io.delta.kernel.engine.Engine
 import io.delta.kernel.exceptions._
 import io.delta.kernel.expressions.Literal
 import io.delta.kernel.expressions.Literal._
+import io.delta.kernel.hook.PostCommitHookType
 import io.delta.kernel.internal.checkpoints.CheckpointerSuite.selectSingleElement
 import io.delta.kernel.internal.util.SchemaUtils.casePreservingPartitionColNames
 import io.delta.kernel.internal.{SnapshotImpl, TableConfig}
@@ -132,9 +133,9 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
       assert(
-        !txnResult.getPostCommitActions.stream()
+        !txnResult.getPostCommitHooks.stream()
           .anyMatch(
-            action => action.getType == PostCommitActionType.CHECKPOINT
+            hook => hook.getType == PostCommitHookType.CHECKPOINT
           )
         )
 
@@ -356,9 +357,9 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
       assert(
-          !txnResult.getPostCommitActions
+        !txnResult.getPostCommitHooks
           .stream()
-          .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
+          .anyMatch(hook => hook.getType == PostCommitHookType.CHECKPOINT)
         )
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))
@@ -378,9 +379,9 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
 
       assert(txnResult.getVersion === 0)
       assert(
-          !txnResult.getPostCommitActions
+        !txnResult.getPostCommitHooks
             .stream()
-            .anyMatch(action => action.getType == PostCommitActionType.CHECKPOINT)
+          .anyMatch(hook => hook.getType == PostCommitHookType.CHECKPOINT)
       )
 
       verifyCommitInfo(tablePath, version = 0)

From 60942c24bf020151e3f204f0a1d647fc8c1efc91 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Mon, 3 Feb 2025 19:06:26 -0800
Subject: [PATCH 11/24] fix doc

---
 .../src/main/java/io/delta/kernel/TransactionCommitResult.java  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 44d8eeaad19..6829a013b64 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -46,7 +46,7 @@ public long getVersion() {
     return version;
   }
 
-  /** @return list of actions to trigger after commit. */
+  /** @return list of operations to trigger after commit. */
   public List<PostCommitHook> getPostCommitHooks() {
     return postCommitHooks;
   }

From ddf351d8f17b83804652d591d2e3270aec408e0d Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Tue, 4 Feb 2025 10:10:32 -0800
Subject: [PATCH 12/24] fix doc

---
 .../src/main/java/io/delta/kernel/hook/PostCommitHook.java      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index 571cb503645..ded632d1b75 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -21,7 +21,7 @@
 
 public interface PostCommitHook {
 
-  /** Invokes the post commit hook, implementation should be thread safe. */
+  /** Invokes the post commit operation whose implementation must be thread safe. */
   void threadSafeInvoke(Engine engine) throws IOException;
 
   PostCommitHookType getType();

From 9ab9587c1bae9b851c1a1decca7cf6fa6151236e Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Tue, 4 Feb 2025 19:24:34 -0800
Subject: [PATCH 13/24] package

---
 .../io/delta/kernel/hook/PostCommitHook.java  |  9 ++++++++
 .../delta/kernel/hook/PostCommitHookType.java | 20 -----------------
 .../kernel/internal/TransactionImpl.java      |  2 +-
 .../{ => internal}/hook/CheckpointHook.java   |  4 +++-
 .../defaults/DeltaTableWriteSuiteBase.scala   | 22 ++++++++++++-------
 .../defaults/DeltaTableWritesSuite.scala      | 21 ++++--------------
 6 files changed, 31 insertions(+), 47 deletions(-)
 delete mode 100644 kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
 rename kernel/kernel-api/src/main/java/io/delta/kernel/{ => internal}/hook/CheckpointHook.java (88%)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index ded632d1b75..49558e30716 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -19,8 +19,17 @@
 import io.delta.kernel.engine.Engine;
 import java.io.IOException;
 
+/**
+ * A hook for executing operation after a transaction commit. Hooks are added in the Transaction and
+ * engine need to invoke the hook explicitly for executing the operation.
+ */
 public interface PostCommitHook {
 
+  enum PostCommitHookType {
+    // Write a new checkpoint at the version committed by the txn if required.
+    CHECKPOINT,
+  }
+
   /** Invokes the post commit operation whose implementation must be thread safe. */
   void threadSafeInvoke(Engine engine) throws IOException;
 
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
deleted file mode 100644
index 749c5efdcc7..00000000000
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHookType.java
+++ /dev/null
@@ -1,20 +0,0 @@
-/*
- * Copyright (2025) The Delta Lake Project Authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package io.delta.kernel.hook;
-
-public enum PostCommitHookType {
-  CHECKPOINT
-}
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
index 60467f711d1..b2bef46757a 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/TransactionImpl.java
@@ -27,11 +27,11 @@
 import io.delta.kernel.engine.Engine;
 import io.delta.kernel.exceptions.ConcurrentWriteException;
 import io.delta.kernel.expressions.Column;
-import io.delta.kernel.hook.CheckpointHook;
 import io.delta.kernel.hook.PostCommitHook;
 import io.delta.kernel.internal.actions.*;
 import io.delta.kernel.internal.data.TransactionStateRow;
 import io.delta.kernel.internal.fs.Path;
+import io.delta.kernel.internal.hook.CheckpointHook;
 import io.delta.kernel.internal.metrics.TransactionMetrics;
 import io.delta.kernel.internal.metrics.TransactionReportImpl;
 import io.delta.kernel.internal.replay.ConflictChecker;
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
similarity index 88%
rename from kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java
rename to kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
index 1ea9a46cb35..4434ab62c84 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/CheckpointHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
@@ -13,13 +13,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.delta.kernel.hook;
+package io.delta.kernel.internal.hook;
 
 import io.delta.kernel.Table;
 import io.delta.kernel.engine.Engine;
+import io.delta.kernel.hook.PostCommitHook;
 import io.delta.kernel.internal.fs.Path;
 import java.io.IOException;
 
+/** Write a new checkpoint at the version committed by the txn if required. */
 public class CheckpointHook implements PostCommitHook {
 
   private final Path tablePath;
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
index be01cc2f4d3..6f24cca7aa1 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWriteSuiteBase.scala
@@ -46,7 +46,7 @@ import io.delta.kernel.types.StructType
 import io.delta.kernel.utils.CloseableIterable.{emptyIterable, inMemoryIterable}
 import io.delta.kernel.utils.CloseableIterator
 import io.delta.kernel.Operation.CREATE_TABLE
-import io.delta.kernel.hook.PostCommitHookType
+import io.delta.kernel.hook.PostCommitHook.PostCommitHookType
 import org.apache.commons.io.FileUtils
 import org.apache.hadoop.conf.Configuration
 import org.apache.hadoop.fs.Path
@@ -411,13 +411,7 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     expVersion: Long,
     expIsReadyForCheckpoint: Boolean): Unit = {
     assert(result.getVersion === expVersion)
-    assert(
-      result.getPostCommitHooks
-        .stream()
-        .anyMatch(
-          hook => hook.getType == PostCommitHookType.CHECKPOINT
-        ) === expIsReadyForCheckpoint
-    )
+    assertCheckpointReadiness(result, expIsReadyForCheckpoint)
   }
 
   def verifyTableProperties(
@@ -439,4 +433,16 @@ trait DeltaTableWriteSuiteBase extends AnyFunSuite with TestUtils {
     builder.append("]")
     checkAnswer(resultProperties, Seq(builder.toString()).map(TestRow(_)))
   }
+
+  def assertCheckpointReadiness(
+      txnResult: TransactionCommitResult,
+      isReadyForCheckpoint: Boolean): Unit = {
+    assert(
+      txnResult.getPostCommitHooks
+        .stream()
+        .anyMatch(
+          hook => hook.getType == PostCommitHookType.CHECKPOINT
+        ) === isReadyForCheckpoint
+    )
+  }
 }
diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index f85585adfe3..487ffc666ca 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -25,7 +25,7 @@ import io.delta.kernel.engine.Engine
 import io.delta.kernel.exceptions._
 import io.delta.kernel.expressions.Literal
 import io.delta.kernel.expressions.Literal._
-import io.delta.kernel.hook.PostCommitHookType
+import io.delta.kernel.hook.PostCommitHook.PostCommitHookType
 import io.delta.kernel.internal.checkpoints.CheckpointerSuite.selectSingleElement
 import io.delta.kernel.internal.util.SchemaUtils.casePreservingPartitionColNames
 import io.delta.kernel.internal.{SnapshotImpl, TableConfig}
@@ -132,12 +132,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(
-        !txnResult.getPostCommitHooks.stream()
-          .anyMatch(
-            hook => hook.getType == PostCommitHookType.CHECKPOINT
-          )
-        )
+      assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
 
       verifyCommitInfo(tablePath = tablePath, version = 0)
       verifyWrittenContent(tablePath, testSchema, Seq.empty)
@@ -356,11 +351,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(
-        !txnResult.getPostCommitHooks
-          .stream()
-          .anyMatch(hook => hook.getType == PostCommitHookType.CHECKPOINT)
-        )
+        assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))
       verifyWrittenContent(tablePath, schema, Seq.empty)
@@ -378,11 +369,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-      assert(
-        !txnResult.getPostCommitHooks
-            .stream()
-          .anyMatch(hook => hook.getType == PostCommitHookType.CHECKPOINT)
-      )
+        assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
 
       verifyCommitInfo(tablePath, version = 0)
       verifyWrittenContent(tablePath, schema, Seq.empty)

From 1d96f5403c8d92f7c7864d8de26cd4edf294d552 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Tue, 4 Feb 2025 19:25:57 -0800
Subject: [PATCH 14/24] ident

---
 .../io/delta/kernel/defaults/DeltaTableWritesSuite.scala      | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
index 487ffc666ca..22f3d07fcd0 100644
--- a/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
+++ b/kernel/kernel-defaults/src/test/scala/io/delta/kernel/defaults/DeltaTableWritesSuite.scala
@@ -351,7 +351,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-        assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
+      assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
 
       verifyCommitInfo(tablePath, version = 0, Seq("Part1", "part2"))
       verifyWrittenContent(tablePath, schema, Seq.empty)
@@ -369,7 +369,7 @@ class DeltaTableWritesSuite extends DeltaTableWriteSuiteBase with ParquetSuiteBa
       val txnResult = txn.commit(engine, emptyIterable())
 
       assert(txnResult.getVersion === 0)
-        assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
+      assertCheckpointReadiness(txnResult, isReadyForCheckpoint = false)
 
       verifyCommitInfo(tablePath, version = 0)
       verifyWrittenContent(tablePath, schema, Seq.empty)

From d8cdaffa9888551c7b7d99cc9992b2fc72695e20 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Tue, 4 Feb 2025 19:53:51 -0800
Subject: [PATCH 15/24] fix import

---
 .../io/delta/kernel/examples/CreateTableAndInsertData.java     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
index 96cf454dc00..c6cce250d4b 100644
--- a/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
+++ b/kernel/examples/kernel-examples/src/main/java/io/delta/kernel/examples/CreateTableAndInsertData.java
@@ -25,7 +25,8 @@
 import io.delta.kernel.data.FilteredColumnarBatch;
 import io.delta.kernel.data.Row;
 import io.delta.kernel.expressions.Literal;
-import io.delta.kernel.hook.*;
+import io.delta.kernel.hook.PostCommitHook;
+import io.delta.kernel.hook.PostCommitHook.PostCommitHookType;
 import io.delta.kernel.utils.*;
 import static io.delta.kernel.examples.utils.Utils.parseArgs;
 

From 8a21a64934b949746ea6596615ac88514440ea46 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 11:16:28 -0800
Subject: [PATCH 16/24] update the doc

---
 .../src/main/java/io/delta/kernel/hook/PostCommitHook.java   | 5 ++++-
 .../java/io/delta/kernel/internal/hook/CheckpointHook.java   | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index 49558e30716..ff97dd5034c 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -26,7 +26,10 @@
 public interface PostCommitHook {
 
   enum PostCommitHookType {
-    // Write a new checkpoint at the version committed by the txn if required.
+    /**
+     * Write a new checkpoint at the version committed by the txn. This hook is present when the
+     * table is ready for checkpoint according to its configured checkpoint interval.
+     */
     CHECKPOINT,
   }
 
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
index 4434ab62c84..bb291422956 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/internal/hook/CheckpointHook.java
@@ -21,7 +21,7 @@
 import io.delta.kernel.internal.fs.Path;
 import java.io.IOException;
 
-/** Write a new checkpoint at the version committed by the txn if required. */
+/** Write a new checkpoint at the version committed by the txn. */
 public class CheckpointHook implements PostCommitHook {
 
   private final Path tablePath;

From 006eb107fc8e53710dd62c40c4b4744acc1f4225 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 14:56:16 -0800
Subject: [PATCH 17/24] update message

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java | 7 ++++++-
 .../src/main/java/io/delta/kernel/hook/PostCommitHook.java | 7 +++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 6829a013b64..84ca4033fe5 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -46,7 +46,12 @@ public long getVersion() {
     return version;
   }
 
-  /** @return list of operations to trigger after commit. */
+  /**
+   * Contains list of operations for kernel based connector to trigger. Connector could trigger the
+   * operations by calling {@link PostCommitHook#threadSafeInvoke(Engine)} in a sync or async way.
+   *
+   * @return list of operations to trigger after commit.
+   */
   public List<PostCommitHook> getPostCommitHooks() {
     return postCommitHooks;
   }
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index ff97dd5034c..d4597cddb11 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -21,14 +21,17 @@
 
 /**
  * A hook for executing operation after a transaction commit. Hooks are added in the Transaction and
- * engine need to invoke the hook explicitly for executing the operation.
+ * engine need to invoke the hook explicitly for executing the operation. Supported operations are
+ * listed in {@link PostCommitHookType}
  */
 public interface PostCommitHook {
 
   enum PostCommitHookType {
     /**
      * Write a new checkpoint at the version committed by the txn. This hook is present when the
-     * table is ready for checkpoint according to its configured checkpoint interval.
+     * table is ready for checkpoint according to its configured checkpoint interval. To perform
+     * this operation, previous checkpoint (if present) and logs after checkpoint will be read to
+     * construct new checkpoint.
      */
     CHECKPOINT,
   }

From fd21ec177319e441df901ae43c30277393c68795 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 15:29:02 -0800
Subject: [PATCH 18/24] update doc

---
 .../java/io/delta/kernel/TransactionCommitResult.java  |  6 +++---
 .../main/java/io/delta/kernel/hook/PostCommitHook.java | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 84ca4033fe5..92737f6b114 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -47,10 +47,10 @@ public long getVersion() {
   }
 
   /**
-   * Contains list of operations for kernel based connector to trigger. Connector could trigger the
-   * operations by calling {@link PostCommitHook#threadSafeInvoke(Engine)} in a sync or async way.
+   * Operations for connector to trigger post-commit. Usage: Call
+   * PostCommitHook#threadSafeInvoke(Engine) either sync or async in a separate thread.
    *
-   * @return list of operations to trigger after commit.
+   * @return list of post-commit operations
    */
   public List<PostCommitHook> getPostCommitHooks() {
     return postCommitHooks;
diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index d4597cddb11..260b61c1dd8 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -28,12 +28,12 @@ public interface PostCommitHook {
 
   enum PostCommitHookType {
     /**
-     * Write a new checkpoint at the version committed by the txn. This hook is present when the
-     * table is ready for checkpoint according to its configured checkpoint interval. To perform
-     * this operation, previous checkpoint (if present) and logs after checkpoint will be read to
-     * construct new checkpoint.
+     * Writes a new checkpoint at the version committed by the transaction. This hook is present
+     * when the table is ready for checkpoint according to its configured checkpoint interval. To
+     * perform this operation, reading previous checkpoint + logs is required to construct a new
+     * checkpoint, with latency scaling based on log size (typically seconds to minutes).
      */
-    CHECKPOINT,
+    CHECKPOINT
   }
 
   /** Invokes the post commit operation whose implementation must be thread safe. */

From c9428e27c6d11612e5953dffc084825191ae2288 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 15:31:57 -0800
Subject: [PATCH 19/24] update doc

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java    | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 92737f6b114..2b31d608912 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -47,8 +47,8 @@ public long getVersion() {
   }
 
   /**
-   * Operations for connector to trigger post-commit. Usage: Call
-   * PostCommitHook#threadSafeInvoke(Engine) either sync or async in a separate thread.
+   * Operations for connector to trigger post-commit.
+   * Usage: Call {@link PostCommitHook#threadSafeInvoke(Engine)} either sync or async in a separate thread.
    *
    * @return list of post-commit operations
    */

From c926f8590b66ae8e8c41de43f07a5d242417b67f Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 15:41:05 -0800
Subject: [PATCH 20/24] fix doc

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 2b31d608912..96460f2cbef 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -48,7 +48,9 @@ public long getVersion() {
 
   /**
    * Operations for connector to trigger post-commit.
-   * Usage: Call {@link PostCommitHook#threadSafeInvoke(Engine)} either sync or async in a separate thread.
+   *
+   * <p>Usage: Call {@link PostCommitHook#threadSafeInvoke(Engine)} either sync or async in a
+   * separate thread.
    *
    * @return list of post-commit operations
    */

From 6cf22c090539bfbb0a4bf9a5da7bde658f0a4962 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 16:02:30 -0800
Subject: [PATCH 21/24] full stop

---
 .../src/main/java/io/delta/kernel/hook/PostCommitHook.java      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
index 260b61c1dd8..173168ff1a0 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/hook/PostCommitHook.java
@@ -22,7 +22,7 @@
 /**
  * A hook for executing operation after a transaction commit. Hooks are added in the Transaction and
  * engine need to invoke the hook explicitly for executing the operation. Supported operations are
- * listed in {@link PostCommitHookType}
+ * listed in {@link PostCommitHookType}.
  */
 public interface PostCommitHook {
 

From b7877817c2bd4b5b3438514185a776e702207201 Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 16:11:38 -0800
Subject: [PATCH 22/24] fix doc

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java   | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 96460f2cbef..91798875a41 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -49,8 +49,9 @@ public long getVersion() {
   /**
    * Operations for connector to trigger post-commit.
    *
-   * <p>Usage: Call {@link PostCommitHook#threadSafeInvoke(Engine)} either sync or async in a
-   * separate thread.
+   * <p>Usage: 1. Async: Call {@link PostCommitHook#threadSafeInvoke(Engine)} in separate thread. 2.
+   * Sync: Direct call {@link PostCommitHook#threadSafeInvoke(Engine)} and block until operation
+   * ends.
    *
    * @return list of post-commit operations
    */

From b09a550bd55e8ff7e291d7a0fbaa2b458f6a778a Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 16:15:19 -0800
Subject: [PATCH 23/24] fix doc

---
 .../main/java/io/delta/kernel/TransactionCommitResult.java | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index 91798875a41..f1c62f203d9 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -49,9 +49,10 @@ public long getVersion() {
   /**
    * Operations for connector to trigger post-commit.
    *
-   * <p>Usage: 1. Async: Call {@link PostCommitHook#threadSafeInvoke(Engine)} in separate thread. 2.
-   * Sync: Direct call {@link PostCommitHook#threadSafeInvoke(Engine)} and block until operation
-   * ends.
+   * <p>Usage:
+   * <li>Async: Call {@link PostCommitHook#threadSafeInvoke(Engine)} in separate thread.
+   * <li>Sync: Direct call {@link PostCommitHook#threadSafeInvoke(Engine)} and block until operation
+   *     ends.
    *
    * @return list of post-commit operations
    */

From d8ce4f53826b7e4f3ab256620e31cda980c07dcb Mon Sep 17 00:00:00 2001
From: Xin Huang <xin.huang@databricks.com>
Date: Wed, 5 Feb 2025 16:17:40 -0800
Subject: [PATCH 24/24] add itemize

---
 .../java/io/delta/kernel/TransactionCommitResult.java    | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
index f1c62f203d9..f95f5b3a537 100644
--- a/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
+++ b/kernel/kernel-api/src/main/java/io/delta/kernel/TransactionCommitResult.java
@@ -50,9 +50,12 @@ public long getVersion() {
    * Operations for connector to trigger post-commit.
    *
    * <p>Usage:
-   * <li>Async: Call {@link PostCommitHook#threadSafeInvoke(Engine)} in separate thread.
-   * <li>Sync: Direct call {@link PostCommitHook#threadSafeInvoke(Engine)} and block until operation
-   *     ends.
+   *
+   * <ul>
+   *   <li>Async: Call {@link PostCommitHook#threadSafeInvoke(Engine)} in separate thread.
+   *   <li>Sync: Direct call {@link PostCommitHook#threadSafeInvoke(Engine)} and block until
+   *       operation ends.
+   * </ul>
    *
    * @return list of post-commit operations
    */