fix(java): panic when reading CreateIndex transaction

java/lance-jni/src/transaction.rs

@@ -394,6 +394,22 @@ fn convert_to_java_operation_inner<'local>(
                 ],
             )?)
         }
+        Operation::CreateIndex {
+            new_indices,
+            removed_indices,
+        } => {
+            let java_new_indices = export_vec(env, &new_indices)?;
+            let java_removed_indices = export_vec(env, &removed_indices)?;
+
+            Ok(env.new_object(
+                "org/lance/operation/CreateIndex",
+                "(Ljava/util/List;Ljava/util/List;)V",
+                &[
+                    JValue::Object(&java_new_indices),
+                    JValue::Object(&java_removed_indices),
+                ],
+            )?)
+        }
         Operation::Update {
             removed_fragment_ids,
             updated_fragments,

java/src/test/java/org/lance/TransactionTest.java

@@ -13,7 +13,12 @@
  */
 package org.lance;
 
+import org.lance.index.IndexOptions;
+import org.lance.index.IndexParams;
+import org.lance.index.IndexType;
+import org.lance.index.scalar.ScalarIndexParams;
 import org.lance.operation.Append;
+import org.lance.operation.CreateIndex;
 
 import org.apache.arrow.memory.RootAllocator;
 import org.junit.jupiter.api.Test;
@@ -25,7 +30,10 @@
 import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertInstanceOf;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class TransactionTest {
 
@@ -63,4 +71,42 @@ public void testTransaction(@TempDir Path tempDir) {
       }
     }
   }
+
+  @Test
+  public void testReadTransactionCreateIndex(@TempDir Path tempDir) {
+    String datasetPath = tempDir.resolve("read_transaction_create_index").toString();
+    try (RootAllocator allocator = new RootAllocator(Long.MAX_VALUE)) {
+      TestUtils.SimpleTestDataset testDataset =
+          new TestUtils.SimpleTestDataset(allocator, datasetPath);
+
+      try (Dataset dataset = testDataset.createEmptyDataset()) {
+        assertEquals(1, dataset.version());
+      }
+
+      try (Dataset dataset = testDataset.write(1, 10)) {
+        ScalarIndexParams scalarParams = ScalarIndexParams.create("btree", "{\"zone_size\": 2048}");
+        IndexParams indexParams = IndexParams.builder().setScalarIndexParams(scalarParams).build();
+
+        dataset.createIndex(
+            IndexOptions.builder(Collections.singletonList("id"), IndexType.BTREE, indexParams)
+                .withIndexName("btree_id_index")
+                .build());
+
+        assertTrue(
+            dataset.listIndexes().contains("btree_id_index"),
+            "Expected 'btree_id_index' to be created");
+
+        Transaction readTx = dataset.readTransaction().orElse(null);
+        assertNotNull(readTx, "readTransaction() should return a transaction for CreateIndex");
+        assertEquals("CreateIndex", readTx.operation().name());
+
+        assertInstanceOf(CreateIndex.class, readTx.operation());
+        CreateIndex op = (CreateIndex) readTx.operation();
+        assertFalse(op.getNewIndices().isEmpty(), "newIndices should not be empty for CreateIndex");
+        assertTrue(
+            op.getRemovedIndices().isEmpty(), "removedIndices should be empty for CreateIndex");
+        assertEquals("btree_id_index", (op.getNewIndices().get(0).name()));
+      }
+    }
+  }
 }