[PECOBLR-839] Fixed getString for boolean column

NEXT_CHANGELOG.md

@@ -14,6 +14,6 @@
 - Databricks SDK dependency upgraded to latest version 0.60.0
 
 ### Fixed
--
+- Fixed `ResultSet.getString` for Boolean columns in Metadata result set.
 ---
 *Note: When making changes, please add your change under the appropriate section with a brief description.* 

src/main/java/com/databricks/jdbc/api/impl/converters/BitConverter.java

@@ -17,7 +17,18 @@ public boolean toBoolean(Object object) throws DatabricksSQLException {
       return Boolean.parseBoolean((String) object);
     }
     throw new DatabricksSQLException(
-        "Unsupported type for conversion to BIT: " + object.getClass(),
+        "Unsupported type for conversion to BIT: " + (object == null ? "null" : object.getClass()),
+        DatabricksDriverErrorCode.UNSUPPORTED_OPERATION);
+  }
+
+  @Override
+  public String toString(Object object) throws DatabricksSQLException {
+    if (object instanceof Boolean) {
+      return object.toString();
+    }
+    throw new DatabricksSQLException(
+        "Unsupported type for conversion to String: "
+            + (object == null ? "null" : object.getClass()),
         DatabricksDriverErrorCode.UNSUPPORTED_OPERATION);
   }
 }

src/test/java/com/databricks/jdbc/api/impl/converters/BitConverterTest.java

@@ -0,0 +1,126 @@
+package com.databricks.jdbc.api.impl.converters;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.databricks.jdbc.exception.DatabricksSQLException;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+public class BitConverterTest {
+
+  private final BitConverter bitConverter = new BitConverter();
+
+  @ParameterizedTest
+  @ValueSource(booleans = {true, false})
+  public void testToStringWithBooleanPrimitives(boolean input) throws DatabricksSQLException {
+    String expected = input ? "true" : "false";
+    assertEquals(expected, bitConverter.toString(input));
+  }
+
+  @ParameterizedTest
+  @CsvSource({"true, true", "false, false"})
+  public void testToStringWithBooleanObjects(String input, String expected)
+      throws DatabricksSQLException {
+    Boolean booleanInput = Boolean.parseBoolean(input);
+    assertEquals(expected, bitConverter.toString(booleanInput));
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+    "null, null",
+    "Object, Object",
+    "int[], class [I",
+    "String[], class [Ljava.lang.String;"
+  })
+  public void testToStringWithUnsupportedTypes(String typeDescription, String expectedInMessage) {
+    Object input = getTestObject(typeDescription);
+
+    DatabricksSQLException exception =
+        assertThrows(DatabricksSQLException.class, () -> bitConverter.toString(input));
+
+    assertTrue(exception.getMessage().contains("Unsupported type for conversion to String"));
+    assertTrue(exception.getMessage().contains(expectedInMessage));
+    assertEquals("UNSUPPORTED_OPERATION", exception.getSQLState());
+  }
+
+  @Test
+  public void testToBooleanWithBooleanTrue() throws DatabricksSQLException {
+    assertTrue(bitConverter.toBoolean(true));
+  }
+
+  @Test
+  public void testToBooleanWithBooleanFalse() throws DatabricksSQLException {
+    assertFalse(bitConverter.toBoolean(false));
+  }
+
+  @Test
+  public void testToBooleanWithBooleanObject() throws DatabricksSQLException {
+    Boolean trueObject = Boolean.TRUE;
+    Boolean falseObject = Boolean.FALSE;
+
+    assertTrue(bitConverter.toBoolean(trueObject));
+    assertFalse(bitConverter.toBoolean(falseObject));
+  }
+
+  @ParameterizedTest
+  @CsvSource({"0, false", "1, true", "-1, true", "42, true", "0.0, false", "3.14, true"})
+  public void testToBooleanWithNumbers(String numberStr, boolean expected)
+      throws DatabricksSQLException {
+    Number number =
+        numberStr.contains(".") ? Double.parseDouble(numberStr) : Integer.parseInt(numberStr);
+    assertEquals(expected, bitConverter.toBoolean(number));
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+    "true, true",
+    "TRUE, true",
+    "True, true",
+    "false, false",
+    "FALSE, false",
+    "False, false",
+    "anything else, false",
+    "'', false",
+    "1, false",
+    "0, false"
+  })
+  public void testToBooleanWithStrings(String input, boolean expected)
+      throws DatabricksSQLException {
+    assertEquals(expected, bitConverter.toBoolean(input));
+  }
+
+  @ParameterizedTest
+  @CsvSource({
+    "null, null",
+    "Object, Object",
+    "int[], class [I",
+    "String[], class [Ljava.lang.String;"
+  })
+  public void testToBooleanWithUnsupportedTypes(String typeDescription, String expectedInMessage) {
+    Object input = getTestObject(typeDescription);
+
+    DatabricksSQLException exception =
+        assertThrows(DatabricksSQLException.class, () -> bitConverter.toBoolean(input));
+
+    assertTrue(exception.getMessage().contains("Unsupported type for conversion to BIT"));
+    assertTrue(exception.getMessage().contains(expectedInMessage));
+    assertEquals("UNSUPPORTED_OPERATION", exception.getSQLState());
+  }
+
+  private Object getTestObject(String typeDescription) {
+    switch (typeDescription) {
+      case "null":
+        return null;
+      case "Object":
+        return new Object();
+      case "int[]":
+        return new int[] {1, 2, 3};
+      case "String[]":
+        return new String[] {"a", "b"};
+      default:
+        throw new IllegalArgumentException("Unknown type: " + typeDescription);
+    }
+  }
+}