feat(java): support drop columns for dataset

java/core/lance-jni/src/blocking_dataset.rs

@@ -657,3 +657,28 @@ fn inner_list_indexes<'local>(
 
     Ok(array_list)
 }
+
+//////////////////////////////
+// Schema evolution Methods //
+//////////////////////////////
+#[no_mangle]
+pub extern "system" fn Java_com_lancedb_lance_Dataset_nativeDropColumns(
+    mut env: JNIEnv,
+    java_dataset: JObject,
+    columns_obj: JObject, // List<String>
+) {
+    ok_or_throw_without_return!(env, inner_drop_columns(&mut env, java_dataset, columns_obj))
+}
+
+fn inner_drop_columns(
+    env: &mut JNIEnv,
+    java_dataset: JObject,
+    columns_obj: JObject, // List<String>
+) -> Result<()> {
+    let columns: Vec<String> = env.get_strings(&columns_obj)?;
+    let columns_slice: Vec<&str> = columns.iter().map(AsRef::as_ref).collect();
+    let mut dataset_guard =
+        unsafe { env.get_rust_field::<_, _, BlockingDataset>(java_dataset, NATIVE_DATASET) }?;
+    RT.block_on(dataset_guard.inner.drop_columns(&columns_slice))?;
+    Ok(())
+}

java/core/src/main/java/com/lancedb/lance/Dataset.java

@@ -253,6 +253,20 @@ public static native Dataset commitAppend(
    */
   public static native void drop(String path, Map<String, String> storageOptions);
 
+  /**
+   * Drop columns from the dataset.
+   *
+   * @param columns The columns to drop
+   */
+  public void dropColumns(List<String> columns) {
+    try (LockManager.WriteLock writeLock = lockManager.acquireWriteLock()) {
+      Preconditions.checkArgument(nativeDatasetHandle != 0, "Dataset is closed");
+      nativeDropColumns(columns);
+    }
+  }
+
+  private native void nativeDropColumns(List<String> columns);
+
   /**
    * Create a new Dataset Scanner.
    *

java/core/src/test/java/com/lancedb/lance/DatasetTest.java

@@ -13,6 +13,9 @@
 
 import org.apache.arrow.memory.BufferAllocator;
 import org.apache.arrow.memory.RootAllocator;
+import org.apache.arrow.vector.types.pojo.ArrowType;
+import org.apache.arrow.vector.types.pojo.Field;
+import org.apache.arrow.vector.types.pojo.Schema;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
@@ -21,7 +24,9 @@
 import java.io.IOException;
 import java.net.URISyntaxException;
 import java.nio.file.Path;
+import java.util.Collections;
 import java.util.HashMap;
+import java.util.stream.Collectors;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -193,6 +198,30 @@ void testGetSchemaWithClosedDataset() {
     }
   }
 
+  @Test
+  void testDropColumns() {
+    String testMethodName = new Object() {}.getClass().getEnclosingMethod().getName();
+    String datasetPath = tempDir.resolve(testMethodName).toString();
+    try (RootAllocator allocator = new RootAllocator(Long.MAX_VALUE)) {
+      TestUtils.SimpleTestDataset testDataset =
+          new TestUtils.SimpleTestDataset(allocator, datasetPath);
+      dataset = testDataset.createEmptyDataset();
+      assertEquals(testDataset.getSchema(), dataset.getSchema());
+      dataset.dropColumns(Collections.singletonList("name"));
+
+      Schema changedSchema =
+          new Schema(
+              Collections.singletonList(Field.nullable("id", new ArrowType.Int(32, true))), null);
+
+      assertEquals(changedSchema.getFields().size(), dataset.getSchema().getFields().size());
+      assertEquals(
+          changedSchema.getFields().stream().map(Field::getName).collect(Collectors.toList()),
+          dataset.getSchema().getFields().stream()
+              .map(Field::getName)
+              .collect(Collectors.toList()));
+    }
+  }
+
   @Test
   void testDropPath() {
     String testMethodName = new Object() {}.getClass().getEnclosingMethod().getName();