Transaction multiGet convert to list-based (#9522)

Summary:
Transaction multiGet convert to list-based.

RocksDB Java (non-transactional) has multiGetAsList() methods to expose multiGet(). These return a list of results. These methods replaced multiGet() methods returning an array of results, which were deprecated in Rocks 6 and are being removed in Rocks 7.

The transactional API still presents multiGet() methods returning arrays, so in Rocks 7 we replace these with multiGetAsList()methods and deprecate the multiGet() methods.

This does not require any changes to the supporting JNI/C++ code, only to the wrappers which present the Java API.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9522

Reviewed By: mrambacher

Differential Revision: D34114373

Pulled By: jay-zhuang

fbshipit-source-id: cb22d6095934d951b6aee4aed3e07923d3c18007

java/src/main/java/org/rocksdb/Transaction.java

@@ -5,6 +5,8 @@
 
 package org.rocksdb;
 
+import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 /**
@@ -310,7 +312,7 @@ public class Transaction extends RocksObject {
 
   /**
    * This function is similar to
-   * {@link RocksDB#multiGet(ReadOptions, List, List)} except it will
+   * {@link RocksDB#multiGetAsList} except it will
    * also read pending changes in this transaction.
    * Currently, this function will return Status::MergeInProgress if the most
    * recent write to the queried key in this batch is a Merge.
@@ -336,9 +338,10 @@ public class Transaction extends RocksObject {
    * @throws IllegalArgumentException thrown if the size of passed keys is not
    *    equal to the amount of passed column family handles.
    */
+  @Deprecated
   public byte[][] multiGet(final ReadOptions readOptions,
-      final List<ColumnFamilyHandle> columnFamilyHandles,
+      final List<ColumnFamilyHandle> columnFamilyHandles, final byte[][] keys)
-      final byte[][] keys) throws RocksDBException {
+      throws RocksDBException {
     assert(isOwningHandle());
     // Check if key size equals cfList size. If not a exception must be
     // thrown. If not a Segmentation fault happens.
@@ -360,7 +363,57 @@ public class Transaction extends RocksObject {
 
   /**
    * This function is similar to
-   * {@link RocksDB#multiGet(ReadOptions, List)} except it will
+   * {@link RocksDB#multiGetAsList(ReadOptions, List, List)} except it will
+   * also read pending changes in this transaction.
+   * Currently, this function will return Status::MergeInProgress if the most
+   * recent write to the queried key in this batch is a Merge.
+   *
+   * If {@link ReadOptions#snapshot()} is not set, the current version of the
+   * key will be read. Calling {@link #setSnapshot()} does not affect the
+   * version of the data returned.
+   *
+   * Note that setting {@link ReadOptions#setSnapshot(Snapshot)} will affect
+   * what is read from the DB but will NOT change which keys are read from this
+   * transaction (the keys in this transaction do not yet belong to any snapshot
+   * and will be fetched regardless).
+   *
+   * @param readOptions Read options.
+   * @param columnFamilyHandles {@link java.util.List} containing
+   *     {@link org.rocksdb.ColumnFamilyHandle} instances.
+   * @param keys of keys for which values need to be retrieved.
+   *
+   * @return Array of values, one for each key
+   *
+   * @throws RocksDBException thrown if error happens in underlying
+   *    native library.
+   * @throws IllegalArgumentException thrown if the size of passed keys is not
+   *    equal to the amount of passed column family handles.
+   */
+
+  public List<byte[]> multiGetAsList(final ReadOptions readOptions,
+      final List<ColumnFamilyHandle> columnFamilyHandles, final List<byte[]> keys)
+      throws RocksDBException {
+    assert (isOwningHandle());
+    // Check if key size equals cfList size. If not a exception must be
+    // thrown. If not a Segmentation fault happens.
+    if (keys.size() != columnFamilyHandles.size()) {
+      throw new IllegalArgumentException("For each key there must be a ColumnFamilyHandle.");
+    }
+    if (keys.size() == 0) {
+      return new ArrayList<>(0);
+    }
+    final byte[][] keysArray = keys.toArray(new byte[keys.size()][]);
+    final long[] cfHandles = new long[columnFamilyHandles.size()];
+    for (int i = 0; i < columnFamilyHandles.size(); i++) {
+      cfHandles[i] = columnFamilyHandles.get(i).nativeHandle_;
+    }
+
+    return Arrays.asList(multiGet(nativeHandle_, readOptions.nativeHandle_, keysArray, cfHandles));
+  }
+
+  /**
+   * This function is similar to
+   * {@link RocksDB#multiGetAsList} except it will
    * also read pending changes in this transaction.
    * Currently, this function will return Status::MergeInProgress if the most
    * recent write to the queried key in this batch is a Merge.
@@ -383,8 +436,9 @@ public class Transaction extends RocksObject {
    * @throws RocksDBException thrown if error happens in underlying
    *    native library.
    */
-  public byte[][] multiGet(final ReadOptions readOptions,
+  @Deprecated
-      final byte[][] keys) throws RocksDBException {
+  public byte[][] multiGet(final ReadOptions readOptions, final byte[][] keys)
+      throws RocksDBException {
     assert(isOwningHandle());
     if(keys.length == 0) {
       return new byte[0][0];
@@ -394,6 +448,41 @@ public class Transaction extends RocksObject {
         keys);
   }
 
+  /**
+   * This function is similar to
+   * {@link RocksDB#multiGetAsList} except it will
+   * also read pending changes in this transaction.
+   * Currently, this function will return Status::MergeInProgress if the most
+   * recent write to the queried key in this batch is a Merge.
+   *
+   * If {@link ReadOptions#snapshot()} is not set, the current version of the
+   * key will be read. Calling {@link #setSnapshot()} does not affect the
+   * version of the data returned.
+   *
+   * Note that setting {@link ReadOptions#setSnapshot(Snapshot)} will affect
+   * what is read from the DB but will NOT change which keys are read from this
+   * transaction (the keys in this transaction do not yet belong to any snapshot
+   * and will be fetched regardless).
+   *
+   * @param readOptions Read options.=
+   *     {@link org.rocksdb.ColumnFamilyHandle} instances.
+   * @param keys of keys for which values need to be retrieved.
+   *
+   * @return Array of values, one for each key
+   *
+   * @throws RocksDBException thrown if error happens in underlying
+   *    native library.
+   */
+  public List<byte[]> multiGetAsList(final ReadOptions readOptions, final List<byte[]> keys)
+      throws RocksDBException {
+    if (keys.size() == 0) {
+      return new ArrayList<>(0);
+    }
+    final byte[][] keysArray = keys.toArray(new byte[keys.size()][]);
+
+    return Arrays.asList(multiGet(nativeHandle_, readOptions.nativeHandle_, keysArray));
+  }
+
   /**
    * Read this key and ensure that this transaction will only
    * be able to be committed if this key is not written outside this
@@ -541,9 +630,10 @@ public class Transaction extends RocksObject {
    * @throws RocksDBException thrown if error happens in underlying
    *    native library.
    */
+  @Deprecated
   public byte[][] multiGetForUpdate(final ReadOptions readOptions,
-      final List<ColumnFamilyHandle> columnFamilyHandles,
+      final List<ColumnFamilyHandle> columnFamilyHandles, final byte[][] keys)
-      final byte[][] keys) throws RocksDBException {
+      throws RocksDBException {
     assert(isOwningHandle());
     // Check if key size equals cfList size. If not a exception must be
     // thrown. If not a Segmentation fault happens.
@@ -562,6 +652,43 @@ public class Transaction extends RocksObject {
         keys, cfHandles);
   }
 
+  /**
+   * A multi-key version of
+   * {@link #getForUpdate(ReadOptions, ColumnFamilyHandle, byte[], boolean)}.
+   *
+   *
+   * @param readOptions Read options.
+   * @param columnFamilyHandles {@link org.rocksdb.ColumnFamilyHandle}
+   *     instances
+   * @param keys the keys to retrieve the values for.
+   *
+   * @return Array of values, one for each key
+   *
+   * @throws RocksDBException thrown if error happens in underlying
+   *    native library.
+   */
+  public List<byte[]> multiGetForUpdateAsList(final ReadOptions readOptions,
+      final List<ColumnFamilyHandle> columnFamilyHandles, final List<byte[]> keys)
+      throws RocksDBException {
+    assert (isOwningHandle());
+    // Check if key size equals cfList size. If not a exception must be
+    // thrown. If not a Segmentation fault happens.
+    if (keys.size() != columnFamilyHandles.size()) {
+      throw new IllegalArgumentException("For each key there must be a ColumnFamilyHandle.");
+    }
+    if (keys.size() == 0) {
+      return new ArrayList<>();
+    }
+    final byte[][] keysArray = keys.toArray(new byte[keys.size()][]);
+
+    final long[] cfHandles = new long[columnFamilyHandles.size()];
+    for (int i = 0; i < columnFamilyHandles.size(); i++) {
+      cfHandles[i] = columnFamilyHandles.get(i).nativeHandle_;
+    }
+    return Arrays.asList(
+        multiGetForUpdate(nativeHandle_, readOptions.nativeHandle_, keysArray, cfHandles));
+  }
+
   /**
    * A multi-key version of {@link #getForUpdate(ReadOptions, byte[], boolean)}.
    *
@@ -574,8 +701,9 @@ public class Transaction extends RocksObject {
    * @throws RocksDBException thrown if error happens in underlying
    *    native library.
    */
-  public byte[][] multiGetForUpdate(final ReadOptions readOptions,
+  @Deprecated
-      final byte[][] keys) throws RocksDBException {
+  public byte[][] multiGetForUpdate(final ReadOptions readOptions, final byte[][] keys)
+      throws RocksDBException {
     assert(isOwningHandle());
     if(keys.length == 0) {
       return new byte[0][0];
@@ -585,6 +713,30 @@ public class Transaction extends RocksObject {
         readOptions.nativeHandle_, keys);
   }
 
+  /**
+   * A multi-key version of {@link #getForUpdate(ReadOptions, byte[], boolean)}.
+   *
+   *
+   * @param readOptions Read options.
+   * @param keys the keys to retrieve the values for.
+   *
+   * @return List of values, one for each key
+   *
+   * @throws RocksDBException thrown if error happens in underlying
+   *    native library.
+   */
+  public List<byte[]> multiGetForUpdateAsList(
+      final ReadOptions readOptions, final List<byte[]> keys) throws RocksDBException {
+    assert (isOwningHandle());
+    if (keys.size() == 0) {
+      return new ArrayList<>(0);
+    }
+
+    final byte[][] keysArray = keys.toArray(new byte[keys.size()][]);
+
+    return Arrays.asList(multiGetForUpdate(nativeHandle_, readOptions.nativeHandle_, keysArray));
+  }
+
   /**
    * Returns an iterator that will iterate on all keys in the default
    * column family including both keys in the DB and uncommitted keys in this

java/src/test/java/org/rocksdb/AbstractTransactionTest.java

@@ -206,12 +206,8 @@ public abstract class AbstractTransactionTest {
 
   @Test
   public void multiGetPut_cf() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
 
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions();
@@ -227,14 +223,31 @@ public abstract class AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetPutAsList_cf() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions();
+         final Transaction txn = dbContainer.beginTransaction()) {
+      final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
+      final List<ColumnFamilyHandle> cfList = Arrays.asList(testCf, testCf);
+
+      assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+          .containsExactly(null, null);
+
+      txn.put(testCf, keys[0], values[0]);
+      txn.put(testCf, keys[1], values[1]);
+      assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+          .containsExactly(values);
+    }
+  }
+
   @Test
   public void multiGetPut() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
 
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions();
@@ -248,6 +261,22 @@ public abstract class AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetPutAsList() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions();
+         final Transaction txn = dbContainer.beginTransaction()) {
+      assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(null, null);
+
+      txn.put(keys[0], values[0]);
+      txn.put(keys[1], values[1]);
+      assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(values);
+    }
+  }
+
   @Test
   public void getForUpdate_cf() throws RocksDBException {
     final byte k1[] = "key1".getBytes(UTF_8);
@@ -495,6 +524,7 @@ public abstract class AbstractTransactionTest {
     }
   }
 
+  @Deprecated
   @Test
   public void multiGetPutUntracked_cf() throws RocksDBException {
     final byte keys[][] = new byte[][] {
@@ -518,14 +548,32 @@ public abstract class AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetPutUntrackedAsList_cf() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions();
+         final Transaction txn = dbContainer.beginTransaction()) {
+      final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
+
+      final List<ColumnFamilyHandle> cfList = Arrays.asList(testCf, testCf);
+
+      assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+          .containsExactly(null, null);
+      txn.putUntracked(testCf, keys[0], values[0]);
+      txn.putUntracked(testCf, keys[1], values[1]);
+      assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+          .containsExactly(values);
+    }
+  }
+
+  @Deprecated
   @Test
   public void multiGetPutUntracked() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
 
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions();
@@ -538,6 +586,21 @@ public abstract class AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetPutAsListUntracked() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions();
+         final Transaction txn = dbContainer.beginTransaction()) {
+      assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(null, null);
+      txn.putUntracked(keys[0], values[0]);
+      txn.putUntracked(keys[1], values[1]);
+      assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(values);
+    }
+  }
+
   @Test
   public void mergeUntracked_cf() throws RocksDBException {
     final byte[] k1 = "key1".getBytes(UTF_8);

java/src/test/java/org/rocksdb/OptimisticTransactionTest.java

@@ -19,9 +19,9 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
 
   @Test
   public void getForUpdate_cf_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
       final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
@@ -57,9 +57,9 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
 
   @Test
   public void getForUpdate_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
 
@@ -92,14 +92,11 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
     }
   }
 
+  @Deprecated
   @Test
   public void multiGetForUpdate_cf_conflict() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
     final byte[] otherValue = "otherValue".getBytes(UTF_8);
 
     try(final DBContainer dbContainer = startDb();
@@ -139,14 +136,54 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetAsListForUpdate_cf_conflict() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+    final byte[] otherValue = "otherValue".getBytes(UTF_8);
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions()) {
+      final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
+      final List<ColumnFamilyHandle> cfList = Arrays.asList(testCf, testCf);
+
+      try (final Transaction txn = dbContainer.beginTransaction()) {
+        txn.put(testCf, keys[0], values[0]);
+        txn.put(testCf, keys[1], values[1]);
+        assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+            .containsExactly(values);
+        txn.commit();
+      }
+
+      try (final Transaction txn2 = dbContainer.beginTransaction()) {
+        try (final Transaction txn3 = dbContainer.beginTransaction()) {
+          assertThat(txn3.multiGetForUpdateAsList(readOptions, cfList, Arrays.asList(keys)))
+              .containsExactly(values);
+
+          // NOTE: txn2 updates k1, during txn3
+          txn2.put(testCf, keys[0], otherValue);
+          assertThat(txn2.get(testCf, readOptions, keys[0])).isEqualTo(otherValue);
+          txn2.commit();
+
+          try {
+            txn3.commit(); // should cause an exception!
+          } catch (final RocksDBException e) {
+            assertThat(e.getStatus().getCode()).isSameAs(Status.Code.Busy);
+            return;
+          }
+        }
+      }
+
+      fail("Expected an exception for put after getForUpdate from conflicting"
+          + "transactions");
+    }
+  }
+
+  @Deprecated
   @Test
   public void multiGetForUpdate_conflict() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
     final byte[] otherValue = "otherValue".getBytes(UTF_8);
 
     try(final DBContainer dbContainer = startDb();
@@ -183,11 +220,50 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetasListForUpdate_conflict() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+    final byte[] otherValue = "otherValue".getBytes(UTF_8);
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions()) {
+      try (final Transaction txn = dbContainer.beginTransaction()) {
+        txn.put(keys[0], values[0]);
+        txn.put(keys[1], values[1]);
+        assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(values);
+        txn.commit();
+      }
+
+      try (final Transaction txn2 = dbContainer.beginTransaction()) {
+        try (final Transaction txn3 = dbContainer.beginTransaction()) {
+          assertThat(txn3.multiGetForUpdateAsList(readOptions, Arrays.asList(keys)))
+              .containsExactly(values);
+
+          // NOTE: txn2 updates k1, during txn3
+          txn2.put(keys[0], otherValue);
+          assertThat(txn2.get(readOptions, keys[0])).isEqualTo(otherValue);
+          txn2.commit();
+
+          try {
+            txn3.commit(); // should cause an exception!
+          } catch (final RocksDBException e) {
+            assertThat(e.getStatus().getCode()).isSameAs(Status.Code.Busy);
+            return;
+          }
+        }
+      }
+
+      fail("Expected an exception for put after getForUpdate from conflicting"
+          + "transactions");
+    }
+  }
+
   @Test
   public void undoGetForUpdate_cf_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
       final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
@@ -220,9 +296,9 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
 
   @Test
   public void undoGetForUpdate_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
 
@@ -261,12 +337,10 @@ public class OptimisticTransactionTest extends AbstractTransactionTest {
 
       try {
         txn.setName(name);
+        fail("Optimistic transactions cannot be named.");
       } catch(final RocksDBException e) {
-         assertThat(e.getStatus().getCode() == Status.Code.InvalidArgument);
+        assertThat(e.getStatus().getCode()).isEqualTo(Status.Code.InvalidArgument);
-        return;
       }
-
-      fail("Optimistic transactions cannot be named.");
     }
   }
 

java/src/test/java/org/rocksdb/TransactionTest.java

@@ -19,9 +19,9 @@ public class TransactionTest extends AbstractTransactionTest {
 
   @Test
   public void getForUpdate_cf_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
       final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
@@ -53,9 +53,9 @@ public class TransactionTest extends AbstractTransactionTest {
 
   @Test
   public void getForUpdate_conflict() throws RocksDBException {
-    final byte k1[] = "key1".getBytes(UTF_8);
+    final byte[] k1 = "key1".getBytes(UTF_8);
-    final byte v1[] = "value1".getBytes(UTF_8);
+    final byte[] v1 = "value1".getBytes(UTF_8);
-    final byte v12[] = "value12".getBytes(UTF_8);
+    final byte[] v12 = "value12".getBytes(UTF_8);
     try(final DBContainer dbContainer = startDb();
         final ReadOptions readOptions = new ReadOptions()) {
 
@@ -86,12 +86,8 @@ public class TransactionTest extends AbstractTransactionTest {
 
   @Test
   public void multiGetForUpdate_cf_conflict() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
     final byte[] otherValue = "otherValue".getBytes(UTF_8);
 
     try(final DBContainer dbContainer = startDb();
@@ -126,14 +122,49 @@ public class TransactionTest extends AbstractTransactionTest {
     }
   }
 
+  @Test
+  public void multiGetAsListForUpdate_cf_conflict() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+    final byte[] otherValue = "otherValue".getBytes(UTF_8);
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions()) {
+      final ColumnFamilyHandle testCf = dbContainer.getTestColumnFamily();
+      final List<ColumnFamilyHandle> cfList = Arrays.asList(testCf, testCf);
+
+      try (final Transaction txn = dbContainer.beginTransaction()) {
+        txn.put(testCf, keys[0], values[0]);
+        txn.put(testCf, keys[1], values[1]);
+        assertThat(txn.multiGetAsList(readOptions, cfList, Arrays.asList(keys)))
+            .containsExactly(values);
+        txn.commit();
+      }
+
+      try (final Transaction txn2 = dbContainer.beginTransaction()) {
+        try (final Transaction txn3 = dbContainer.beginTransaction()) {
+          assertThat(txn3.multiGetForUpdateAsList(readOptions, cfList, Arrays.asList(keys)))
+              .containsExactly(values);
+
+          // NOTE: txn2 updates k1, during txn3
+          try {
+            txn2.put(testCf, keys[0], otherValue); // should cause an exception!
+          } catch (final RocksDBException e) {
+            assertThat(e.getStatus().getCode()).isSameAs(Status.Code.TimedOut);
+            return;
+          }
+        }
+      }
+
+      fail("Expected an exception for put after getForUpdate from conflicting"
+          + "transactions");
+    }
+  }
+
   @Test
   public void multiGetForUpdate_conflict() throws RocksDBException {
-    final byte keys[][] = new byte[][] {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
-        "key1".getBytes(UTF_8),
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
-        "key2".getBytes(UTF_8)};
-    final byte values[][] = new byte[][] {
-        "value1".getBytes(UTF_8),
-        "value2".getBytes(UTF_8)};
     final byte[] otherValue = "otherValue".getBytes(UTF_8);
 
     try(final DBContainer dbContainer = startDb();
@@ -160,6 +191,41 @@ public class TransactionTest extends AbstractTransactionTest {
         }
       }
 
+      fail("Expected an exception for put after getForUpdate from conflicting"
+          + "transactions");
+    }
+  }
+
+  @Test
+  public void multiGetAsListForUpdate_conflict() throws RocksDBException {
+    final byte[][] keys = new byte[][] {"key1".getBytes(UTF_8), "key2".getBytes(UTF_8)};
+    final byte[][] values = new byte[][] {"value1".getBytes(UTF_8), "value2".getBytes(UTF_8)};
+    final byte[] otherValue = "otherValue".getBytes(UTF_8);
+
+    try (final DBContainer dbContainer = startDb();
+         final ReadOptions readOptions = new ReadOptions()) {
+      try (final Transaction txn = dbContainer.beginTransaction()) {
+        txn.put(keys[0], values[0]);
+        txn.put(keys[1], values[1]);
+        assertThat(txn.multiGetAsList(readOptions, Arrays.asList(keys))).containsExactly(values);
+        txn.commit();
+      }
+
+      try (final Transaction txn2 = dbContainer.beginTransaction()) {
+        try (final Transaction txn3 = dbContainer.beginTransaction()) {
+          assertThat(txn3.multiGetForUpdateAsList(readOptions, Arrays.asList(keys)))
+              .containsExactly(values);
+
+          // NOTE: txn2 updates k1, during txn3
+          try {
+            txn2.put(keys[0], otherValue); // should cause an exception!
+          } catch(final RocksDBException e) {
+            assertThat(e.getStatus().getCode()).isSameAs(Status.Code.TimedOut);
+            return;
+          }
+        }
+      }
+
       fail("Expected an exception for put after getForUpdate from conflicting" +
           "transactions");
     }