GH-35932: [Java] Make JDBC test less brittle (#35940)

### Rationale for this change

A JDBC test is brittle because it compares string representations.

### What changes are included in this PR?

Compare values directly.

### Are these changes tested?

N/A

### Are there any user-facing changes?

No.
* Closes: #35932

Authored-by: David Li <[email protected]>
Signed-off-by: Raúl Cumplido <[email protected]>

Author: lidavidm

dev/release/verify-release-candidate.sh

@@ -563,7 +563,10 @@ test_package_java() {
   show_header "Build and test Java libraries"
 
   # Build and test Java (Requires newer Maven -- I used 3.3.9)
-  maybe_setup_conda maven || exit 1
+  # Pin OpenJDK 17 since OpenJDK 20 is incompatible with our versions
+  # of things like Mockito, and we also can't update Mockito due to
+  # not supporting Java 8 anymore
+  maybe_setup_conda maven openjdk=17.0.3 || exit 1
 
   pushd java
   mvn test

java/adapter/jdbc/src/test/java/org/apache/arrow/adapter/jdbc/JdbcToArrowCommentMetadataTest.java

@@ -29,6 +29,7 @@
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -37,18 +38,18 @@
 import java.util.Set;
 
 import org.apache.arrow.memory.RootAllocator;
+import org.apache.arrow.vector.types.Types;
+import org.apache.arrow.vector.types.pojo.ArrowType;
+import org.apache.arrow.vector.types.pojo.Field;
+import org.apache.arrow.vector.types.pojo.FieldType;
 import org.apache.arrow.vector.types.pojo.Schema;
-import org.apache.arrow.vector.util.ObjectMapperFactory;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
-import com.fasterxml.jackson.databind.ObjectWriter;
-
 public class JdbcToArrowCommentMetadataTest {
 
   private static final String COMMENT = "comment"; //use this metadata key for interoperability with Spark StructType
-  private final ObjectWriter schemaSerializer = ObjectMapperFactory.newObjectMapper().writerWithDefaultPrettyPrinter();
   private Connection conn = null;
 
   /**
@@ -73,26 +74,85 @@ public void tearDown() throws SQLException {
     }
   }
 
+  private static Field field(String name, boolean nullable, ArrowType type, Map<String, String> metadata) {
+    return new Field(name, new FieldType(nullable, type, null, metadata), Collections.emptyList());
+  }
+
+  private static Map<String, String> metadata(String... entries) {
+    if (entries.length % 2 != 0) {
+      throw new IllegalArgumentException("Map must have equal number of keys and values");
+    }
+
+    final Map<String, String> result = new HashMap<>();
+    for (int i = 0; i < entries.length; i += 2) {
+      result.put(entries[i], entries[i + 1]);
+    }
+    return result;
+  }
+
   @Test
   public void schemaComment() throws Exception {
     boolean includeMetadata = false;
-    String schemaJson = schemaSerializer.writeValueAsString(getSchemaWithCommentFromQuery(includeMetadata));
-    String expectedSchema = getExpectedSchema("/h2/expectedSchemaWithComments.json");
-    assertThat(schemaJson).isEqualTo(expectedSchema);
+    Schema schema = getSchemaWithCommentFromQuery(includeMetadata);
+    Schema expectedSchema = new Schema(Arrays.asList(
+        field("ID", false, Types.MinorType.BIGINT.getType(),
+            metadata("comment", "Record identifier")),
+        field("NAME", true, Types.MinorType.VARCHAR.getType(),
+            metadata("comment", "Name of record")),
+        field("COLUMN1", true, Types.MinorType.BIT.getType(),
+            metadata()),
+        field("COLUMNN", true, Types.MinorType.INT.getType(),
+            metadata("comment", "Informative description of columnN"))
+        ), metadata("comment", "This is super special table with valuable data"));
+    assertThat(schema).isEqualTo(expectedSchema);
   }
 
   @Test
   public void schemaCommentWithDatabaseMetadata() throws Exception {
     boolean includeMetadata = true;
-    String schemaJson = schemaSerializer.writeValueAsString(getSchemaWithCommentFromQuery(includeMetadata));
-    String expectedSchema = getExpectedSchema("/h2/expectedSchemaWithCommentsAndJdbcMeta.json");
+    Schema schema = getSchemaWithCommentFromQuery(includeMetadata);
+    Schema expectedSchema = new Schema(Arrays.asList(
+        field("ID", false, Types.MinorType.BIGINT.getType(),
+            metadata(
+                "SQL_CATALOG_NAME", "JDBCTOARROWTEST?CHARACTERENCODING=UTF-8",
+                "SQL_SCHEMA_NAME", "PUBLIC",
+                "SQL_TABLE_NAME", "TABLE1",
+                "SQL_COLUMN_NAME", "ID",
+                "SQL_TYPE", "BIGINT",
+                "comment", "Record identifier"
+            )),
+        field("NAME", true, Types.MinorType.VARCHAR.getType(),
+            metadata(
+                "SQL_CATALOG_NAME", "JDBCTOARROWTEST?CHARACTERENCODING=UTF-8",
+                "SQL_SCHEMA_NAME", "PUBLIC",
+                "SQL_TABLE_NAME", "TABLE1",
+                "SQL_COLUMN_NAME", "NAME",
+                "SQL_TYPE", "VARCHAR",
+                "comment", "Name of record")),
+        field("COLUMN1", true, Types.MinorType.BIT.getType(),
+            metadata(
+                "SQL_CATALOG_NAME", "JDBCTOARROWTEST?CHARACTERENCODING=UTF-8",
+                "SQL_SCHEMA_NAME", "PUBLIC",
+                "SQL_TABLE_NAME", "TABLE1",
+                "SQL_COLUMN_NAME", "COLUMN1",
+                "SQL_TYPE", "BOOLEAN")),
+        field("COLUMNN", true, Types.MinorType.INT.getType(),
+            metadata(
+                "SQL_CATALOG_NAME", "JDBCTOARROWTEST?CHARACTERENCODING=UTF-8",
+                "SQL_SCHEMA_NAME", "PUBLIC",
+                "SQL_TABLE_NAME", "TABLE1",
+                "SQL_COLUMN_NAME", "COLUMNN",
+                "SQL_TYPE", "INTEGER",
+                "comment", "Informative description of columnN"))
+    ), metadata("comment", "This is super special table with valuable data"));
+    assertThat(schema).isEqualTo(expectedSchema);
     /* corresponding Apache Spark DDL after conversion:
         ID BIGINT NOT NULL COMMENT 'Record identifier',
         NAME STRING COMMENT 'Name of record',
         COLUMN1 BOOLEAN,
         COLUMNN INT COMMENT 'Informative description of columnN'
      */
-    assertThat(schemaJson).isEqualTo(expectedSchema);
+    assertThat(schema).isEqualTo(expectedSchema);
   }
 
   private Schema getSchemaWithCommentFromQuery(boolean includeMetadata) throws SQLException {

java/adapter/jdbc/src/test/resources/h2/expectedSchemaWithComments.json

@@ -56,6 +56,8 @@
 import org.apache.arrow.vector.types.pojo.Schema;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnOs;
+import org.junit.jupiter.api.condition.OS;
 
 import com.google.common.base.Charsets;
 import com.google.protobuf.ByteString;
@@ -270,6 +272,7 @@ public void getStream() throws Exception {
 
   /** Ensure the client is configured to accept large messages. */
   @Test
+  @DisabledOnOs(value = {OS.WINDOWS}, disabledReason = "https://github.com/apache/arrow/issues/33237: flaky test")
   public void getStreamLargeBatch() throws Exception {
     test(c -> {
       try (final FlightStream stream = c.getStream(new Ticket(Producer.TICKET_LARGE_BATCH))) {

java/adapter/jdbc/src/test/resources/h2/expectedSchemaWithCommentsAndJdbcMeta.json

@@ -32,6 +32,7 @@
 import org.junit.Before;
 import org.junit.BeforeClass;
 import org.junit.ClassRule;
+import org.junit.Ignore;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.ErrorCollector;
@@ -73,6 +74,7 @@ public void testSimpleQueryNoParameterBinding() throws SQLException {
   }
 
   @Test
+  @Ignore("https://github.com/apache/arrow/issues/34741: flaky test")
   public void testPreparedStatementExecutionOnce() throws SQLException {
     final PreparedStatement statement = connection.prepareStatement(CoreMockedSqlProducers.LEGACY_REGULAR_SQL_CMD);
     // Expect that there is one entry in the map -- {prepared statement action type, invocation count}.