Object ID Identicy conversion to long fails on old schema

This change fixed a bug which tried to convert non-string object as string

Fixes gh-7621

acl/src/main/java/org/springframework/security/acls/jdbc/AclClassIdUtils.java

@@ -118,7 +118,7 @@ class AclClassIdUtils {
 	 */
 	private Long convertToLong(Serializable identifier) {
 		Long idAsLong;
-		if (canConvertFromStringTo(Long.class)) {
+		if (conversionService.canConvert(identifier.getClass(), Long.class)) {
 			idAsLong = conversionService.convert(identifier, Long.class);
 		} else {
 			idAsLong = Long.valueOf(identifier.toString());

acl/src/test/java/org/springframework/security/acls/jdbc/AclClassIdUtilsTest.java

@@ -24,6 +24,7 @@ import org.mockito.junit.MockitoJUnitRunner;
 import org.springframework.core.convert.ConversionService;
 
 import java.io.Serializable;
+import java.math.BigInteger;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.UUID;
@@ -39,6 +40,7 @@ import static org.mockito.BDDMockito.given;
 public class AclClassIdUtilsTest {
 
 	private static final Long DEFAULT_IDENTIFIER = 999L;
+	private static final BigInteger BIGINT_IDENTIFIER = new BigInteger("999");
 	private static final String DEFAULT_IDENTIFIER_AS_STRING = DEFAULT_IDENTIFIER.toString();
 
 	@Mock
@@ -62,6 +64,15 @@ public class AclClassIdUtilsTest {
 		assertThat(newIdentifier).isEqualTo(DEFAULT_IDENTIFIER);
 	}
 
+	@Test
+	public void shouldReturnLongIfIdentifierIsBigInteger() throws SQLException {
+		// when
+		Serializable newIdentifier = aclClassIdUtils.identifierFrom(BIGINT_IDENTIFIER, resultSet);
+
+		// then
+		assertThat(newIdentifier).isEqualTo(DEFAULT_IDENTIFIER);
+	}
+
 	@Test
 	public void shouldReturnLongIfClassIdTypeIsNull() throws SQLException {
 		// given