Fix errorprone and Javadoc warnings

data-loader/cli/src/main/java/com/scalar/db/dataloader/cli/command/dataexport/ExportCommand.java

@@ -45,7 +45,6 @@
 @CommandLine.Command(name = "export", description = "export data from a ScalarDB table")
 public class ExportCommand extends ExportCommandOptions implements Callable<Integer> {
 
-  private static final String EXPORT_FILE_NAME_FORMAT = "export.%s.%s.%s.%s";
   private static final Logger logger = LoggerFactory.getLogger(ExportCommand.class);
 
   @Spec CommandSpec spec;
@@ -169,11 +168,8 @@ private String getOutputAbsoluteFilePath(
     String fileName =
         StringUtils.isBlank(outputFileName)
             ? String.format(
-                EXPORT_FILE_NAME_FORMAT,
-                namespace,
-                table,
-                System.nanoTime(),
-                outputFormat.toString().toLowerCase())
+                "export.%s.%s.%s.%s",
+                namespace, table, System.nanoTime(), outputFormat.toString().toLowerCase())
             : outputFileName;
 
     if (StringUtils.isBlank(outputDirectory)) {

data-loader/cli/src/main/java/com/scalar/db/dataloader/cli/command/dataexport/ScanOrderingConverter.java

@@ -7,14 +7,31 @@
 import java.util.stream.Collectors;
 import picocli.CommandLine;
 
+/**
+ * A {@link picocli.CommandLine.ITypeConverter} implementation that converts a comma-separated
+ * string of column-order pairs into a list of {@link com.scalar.db.api.Scan.Ordering} objects.
+ *
+ * <p>This converter is used to parse CLI arguments for scan ordering in ScalarDB-based
+ * applications. The input string must contain one or more key-value pairs in the format {@code
+ * column=order}, separated by commas. The {@code order} must be a valid {@link
+ * com.scalar.db.api.Scan.Ordering.Order} enum value, such as {@code ASC} or {@code DESC}
+ * (case-insensitive).
+ *
+ * <p>Example input: {@code "name=asc,age=desc"} results in a list containing {@code
+ * Scan.Ordering.asc("name")} and {@code Scan.Ordering.desc("age")}.
+ *
+ * <p>Invalid formats or unrecognized order values will result in an {@link
+ * IllegalArgumentException}.
+ */
 public class ScanOrderingConverter implements CommandLine.ITypeConverter<List<Scan.Ordering>> {
   /**
-   * Converts a comma-separated string of key-value pairs into a list of {@link Scan.Ordering}
-   * objects. Each pair must be in the format "column=order", where "order" is a valid enum value of
-   * {@link Scan.Ordering.Order} (e.g., ASC or DESC, case-insensitive).
+   * Converts a comma-separated string of key-value pairs into a list of {@link
+   * com.scalar.db.api.Scan.Ordering} objects. Each pair must be in the format "column=order", where
+   * "order" is a valid enum value of {@link com.scalar.db.api.Scan.Ordering} (e.g., ASC or DESC,
+   * case-insensitive).
    *
    * @param value the comma-separated key-value string to convert
-   * @return a list of {@link Scan.Ordering} objects constructed from the input
+   * @return a list of {@link com.scalar.db.api.Scan.Ordering} objects constructed from the input
    * @throws IllegalArgumentException if parsing fails due to invalid format or enum value
    */
   @Override
@@ -26,7 +43,9 @@ public List<Scan.Ordering> convert(String value) {
               String columnName = entry.getKey();
               Scan.Ordering.Order sortOrder =
                   Scan.Ordering.Order.valueOf(entry.getValue().trim().toUpperCase());
-              return new Scan.Ordering(columnName, sortOrder);
+              return sortOrder == Scan.Ordering.Order.ASC
+                  ? Scan.Ordering.asc(columnName)
+                  : Scan.Ordering.desc(columnName);
             })
         .collect(Collectors.toList());
   }

data-loader/cli/src/main/java/com/scalar/db/dataloader/cli/util/CommandLineInputUtils.java

@@ -13,7 +13,7 @@ public class CommandLineInputUtils {
    * Parses a single key-value pair from a string in the format "key=value".
    *
    * @param keyValue the key-value string to parse
-   * @return a {@link Map.Entry} representing the parsed key-value pair
+   * @return a {@link java.util.Map.Entry} representing the parsed key-value pair
    * @throws IllegalArgumentException if the input is null, empty, or not in the expected format
    */
   public static Map.Entry<String, String> parseKeyValue(String keyValue) {
@@ -50,7 +50,7 @@ public static String[] splitByDelimiter(String value, String delimiter, int limi
 
   /**
    * Validates that a given integer value is positive. If the value is less than 1, it throws a
-   * {@link CommandLine.ParameterException} with the specified error message.
+   * {@link picocli.CommandLine.ParameterException} with the specified error message.
    *
    * @param commandLine the {@link CommandLine} instance used to provide context for the exception
    * @param value the integer value to validate

data-loader/cli/src/test/java/com/scalar/db/dataloader/cli/command/dataexport/ScanOrderingConverterTest.java

@@ -29,16 +29,15 @@ void callConvert_withInvalidValue_shouldThrowException() {
   void callConvert_withValidValueAndOrderAscending_shouldReturnScanOrdering() {
     String value = "id=ASC,age=DESC";
     List<Scan.Ordering> expectedOrder = new ArrayList<>();
-    expectedOrder.add(new Scan.Ordering("id", Scan.Ordering.Order.ASC));
-    expectedOrder.add(new Scan.Ordering("age", Scan.Ordering.Order.DESC));
+    expectedOrder.add(Scan.Ordering.asc("id"));
+    expectedOrder.add(Scan.Ordering.desc("age"));
     Assertions.assertEquals(expectedOrder, scanOrderingConverter.convert(value));
   }
 
   @Test
   void callConvert_withValidValueAndOrderDescending_shouldReturnScanOrdering() {
     String value = "id=desc";
-    List<Scan.Ordering> expectedOrder =
-        Collections.singletonList(new Scan.Ordering("id", Scan.Ordering.Order.DESC));
+    List<Scan.Ordering> expectedOrder = Collections.singletonList(Scan.Ordering.desc("id"));
     Assertions.assertEquals(expectedOrder, scanOrderingConverter.convert(value));
   }
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/ColumnInfo.java

@@ -9,6 +9,7 @@
  * <p>This class holds the metadata for a column, including the namespace (schema), table name, and
  * the column name within the table.
  */
+@SuppressWarnings("SameNameButDifferent")
 @Value
 @Builder
 public class ColumnInfo {

data-loader/core/src/main/java/com/scalar/db/dataloader/core/Constants.java

@@ -2,26 +2,18 @@
 
 /** The constants that are used in the com.scalar.dataloader.core package */
 public class Constants {
-
-  public static final String IMPORT_LOG_ENTRY_STATUS_FIELD = "data_loader_import_status";
+  /**
+   * Format string used for table lookup keys. It expects two string arguments: the namespace and
+   * the table name, respectively.
+   *
+   * <p>Example: {@code String.format(TABLE_LOOKUP_KEY_FORMAT, "ns", "table")} will result in
+   * "ns.table".
+   */
   public static final String TABLE_LOOKUP_KEY_FORMAT = "%s.%s";
-
-  public static final String LOG_UPDATE_SUCCESS = "Row %s has been updated in table %s.%s";
-  public static final String LOG_INSERT_SUCCESS = "Row %s has been inserted into table %s.%s";
-  public static final String LOG_IMPORT_VALIDATION = "Validating data for line %s ...";
-  public static final String LOG_IMPORT_GET_DATA =
-      "Retrieving existing data record from database ...";
-  public static final String LOG_IMPORT_LINE_SUCCESS = "Row %s import is completed";
-  public static final String LOG_IMPORT_LINE_FAILED = "Row %s import has failed: %s";
-  public static final String LOG_IMPORT_COMPLETED =
-      "The import process has been completed. Please check the success and failed output files for a detailed report";
-
-  public static final String LOG_SCANNING_START = "Retrieving data from %s.%s table ...";
-  public static final String LOG_CONVERTING = "Converting %s.%s data to %s ...";
-  public static final String MISSING_CSV_HEADERS =
-      "Valid headers are not present or missing in the provided CSV file";
-  public static final String ERROR_MISSING_SOURCE_FIELD =
-      "the data mapping source field '%s' for table '%s' is missing in the json data record";
+  /**
+   * Status message used to indicate that a transaction was aborted as part of a batch transaction
+   * failure.
+   */
   public static final String ABORT_TRANSACTION_STATUS =
       "Transaction aborted as part of batch transaction aborted";
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/DataLoaderObjectMapper.java

@@ -4,8 +4,29 @@
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 
+/**
+ * A custom {@link ObjectMapper} used for data loading operations.
+ *
+ * <p>This mapper is configured to:
+ *
+ * <ul>
+ *   <li>Exclude {@code null} values during serialization
+ *   <li>Support Java 8 date/time types via {@link JavaTimeModule}
+ * </ul>
+ *
+ * <p>It can be reused wherever consistent JSON serialization/deserialization behavior is needed.
+ */
 public class DataLoaderObjectMapper extends ObjectMapper {
 
+  /**
+   * Constructs a {@code DataLoaderObjectMapper} with default settings, including:
+   *
+   * <ul>
+   *   <li>{@link com.fasterxml.jackson.annotation.JsonInclude.Include#NON_NULL} to skip {@code
+   *       null} values
+   *   <li>{@link JavaTimeModule} registration to handle Java 8 date/time types
+   * </ul>
+   */
   public DataLoaderObjectMapper() {
     super();
     this.setSerializationInclusion(JsonInclude.Include.NON_NULL);

data-loader/core/src/main/java/com/scalar/db/dataloader/core/DatabaseKeyType.java

@@ -2,6 +2,9 @@
 
 /** Type of key in database */
 public enum DatabaseKeyType {
+  /** Represents a partition key, which determines the partition where the data is stored. */
   PARTITION,
+
+  /** Represents a clustering key, which determines the order of data within a partition. */
   CLUSTERING
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/FileFormat.java

@@ -2,7 +2,21 @@
 
 /** The available input and output formats for the data loader import and export commands */
 public enum FileFormat {
+  /**
+   * JSON (JavaScript Object Notation) format. Typically, represents the entire dataset as a single
+   * JSON array or object.
+   */
   JSON,
+
+  /**
+   * JSON Lines (JSONL) format. Each line is a separate JSON object, making it suitable for
+   * streaming large datasets.
+   */
   JSONL,
+
+  /**
+   * CSV (Comma-Separated Values) format. A plain text format where each line represents a row and
+   * columns are separated by commas.
+   */
   CSV
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/ScalarDbMode.java

@@ -1,7 +1,20 @@
 package com.scalar.db.dataloader.core;
 
-/** The available modes a ScalarDB instance can run in */
+/**
+ * The available modes a ScalarDB instance can run in. Determines how ScalarDB interacts with the
+ * underlying database.
+ */
 public enum ScalarDbMode {
+
+  /**
+   * Storage mode: Operates directly on the underlying storage engine without transactional
+   * guarantees. Suitable for raw data access and simple CRUD operations.
+   */
   STORAGE,
+
+  /**
+   * Transaction mode: Provides transaction management with ACID guarantees across multiple
+   * operations. Suitable for applications that require consistency and atomicity.
+   */
   TRANSACTION
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/ScanRange.java

@@ -3,7 +3,8 @@
 import com.scalar.db.io.Key;
 import lombok.Value;
 
-/** * The scan range which is used in data export scan filtering */
+/** The scan range which is used in data export scan filtering */
+@SuppressWarnings("SameNameButDifferent")
 @Value
 public class ScanRange {
   /** The key for scan start filter */

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/CsvExportManager.java

@@ -11,7 +11,17 @@
 import java.util.Iterator;
 import java.util.List;
 
+/** Export manager implementation which manages the export task that exports data in CSV format */
 public class CsvExportManager extends ExportManager {
+
+  /**
+   * Constructs a {@code CsvExportManager} with the specified {@link DistributedStorage}, {@link
+   * ScalarDbDao}, and {@link ProducerTaskFactory}.
+   *
+   * @param storage the {@code DistributedStorage} instance used to read data from the database
+   * @param dao the {@code ScalarDbDao} used to execute export-related database operations
+   * @param producerTaskFactory the factory used to create producer tasks for exporting data
+   */
   public CsvExportManager(
       DistributedStorage storage, ScalarDbDao dao, ProducerTaskFactory producerTaskFactory) {
     super(storage, dao, producerTaskFactory);

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/ExportManager.java

@@ -28,6 +28,8 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+/** Export manager class which manages the export task */
+@SuppressWarnings({"SameNameButDifferent", "FutureReturnValueIgnored"})
 @RequiredArgsConstructor
 public abstract class ExportManager {
   private static final Logger logger = LoggerFactory.getLogger(ExportManager.class);
@@ -64,6 +66,7 @@ abstract void processFooter(
    * @param exportOptions Export options
    * @param tableMetadata Metadata for a single ScalarDB table
    * @param writer Writer to write the exported data
+   * @return export report object containing data such as total exported row count
    */
   public ExportReport startExport(
       ExportOptions exportOptions, TableMetadata tableMetadata, Writer writer) {

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/ExportOptions.java

@@ -9,8 +9,8 @@
 import lombok.Builder;
 import lombok.Data;
 
-/** Options for a ScalarDB export data operation */
-@SuppressWarnings("SameNameButDifferent")
+/** Options for a ScalarDB export data operation. */
+@SuppressWarnings({"SameNameButDifferent", "MissingSummary"})
 @Builder(builderMethodName = "hiddenBuilder")
 @Data
 public class ExportOptions {
@@ -31,6 +31,15 @@ public class ExportOptions {
   @Builder.Default private List<String> projectionColumns = Collections.emptyList();
   private List<Scan.Ordering> sortOrders;
 
+  /**
+   * Generates and returns an export options builder.
+   *
+   * @param namespace namespaces for export
+   * @param tableName tableName for export
+   * @param scanPartitionKey scan partition key for export
+   * @param outputFileFormat output file format for export
+   * @return a configured export options builder
+   */
   public static ExportOptionsBuilder builder(
       String namespace, String tableName, Key scanPartitionKey, FileFormat outputFileFormat) {
     return hiddenBuilder()
@@ -39,4 +48,13 @@ public static ExportOptionsBuilder builder(
         .scanPartitionKey(scanPartitionKey)
         .outputFileFormat(outputFileFormat);
   }
+
+  /**
+   * Explicit builder class declaration required for Javadoc generation.
+   *
+   * <p>Although Lombok generates this builder class automatically, Javadoc requires an explicit
+   * declaration to resolve references in the generated documentation, especially when using a
+   * custom builder method name (e.g., {@code hiddenBuilder()}).
+   */
+  public static class ExportOptionsBuilder {}
 }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/ExportReport.java

@@ -16,10 +16,20 @@ public class ExportReport {
    */
   private final LongAdder exportedRowCount = new LongAdder();
 
+  /**
+   * Returns the total number of rows that have been exported so far.
+   *
+   * @return the cumulative exported row count
+   */
   public long getExportedRowCount() {
     return exportedRowCount.sum();
   }
 
+  /**
+   * Increments the exported row count by the specified value.
+   *
+   * @param count the number of rows to add to the exported count
+   */
   public void updateExportedRowCount(long count) {
     this.exportedRowCount.add(count);
   }

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/JsonExportManager.java

@@ -7,7 +7,17 @@
 import java.io.IOException;
 import java.io.Writer;
 
+/** Export manager implementation which manages the export task that exports data in JSON format */
 public class JsonExportManager extends ExportManager {
+
+  /**
+   * Constructs a {@code JsonExportManager} with the specified {@link DistributedStorage}, {@link
+   * ScalarDbDao}, and {@link ProducerTaskFactory}.
+   *
+   * @param storage the {@code DistributedStorage} instance used to read data from the database
+   * @param dao the {@code ScalarDbDao} used to execute export-related database operations
+   * @param producerTaskFactory the factory used to create producer tasks for exporting data
+   */
   public JsonExportManager(
       DistributedStorage storage, ScalarDbDao dao, ProducerTaskFactory producerTaskFactory) {
     super(storage, dao, producerTaskFactory);

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/JsonLineExportManager.java

@@ -7,7 +7,19 @@
 import java.io.IOException;
 import java.io.Writer;
 
+/**
+ * Export manager implementation which manages the export task that exports data in JSONLines format
+ */
 public class JsonLineExportManager extends ExportManager {
+
+  /**
+   * Constructs a {@code JsonLineExportManager} with the specified {@link DistributedStorage},
+   * {@link ScalarDbDao}, and {@link ProducerTaskFactory}.
+   *
+   * @param storage the {@code DistributedStorage} instance used to read data from the database
+   * @param dao the {@code ScalarDbDao} used to execute export-related database operations
+   * @param producerTaskFactory the factory used to create producer tasks for exporting data
+   */
   public JsonLineExportManager(
       DistributedStorage storage, ScalarDbDao dao, ProducerTaskFactory producerTaskFactory) {
     super(storage, dao, producerTaskFactory);

data-loader/core/src/main/java/com/scalar/db/dataloader/core/dataexport/producer/CsvProducerTask.java

@@ -34,6 +34,7 @@ public class CsvProducerTask extends ProducerTask {
    * Class constructor
    *
    * @param includeMetadata Include metadata in the exported data
+   * @param projectColumns list of columns that is required in export data
    * @param tableMetadata Metadata for a single ScalarDB table
    * @param columnDataTypes Map of data types for the all columns in a ScalarDB table
    * @param delimiter Delimiter used in csv content