clean up very old Dialect javadoc

and squash a couple of warnings

hibernate-core/src/main/java/org/hibernate/dialect/CockroachDialect.java

@@ -62,7 +62,7 @@ import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTime;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTimestampWithMicros;
 
 /**
- * A dialect for CockroachDB.
+ * A {@linkplain Dialect SQL dialect} for CockroachDB.
  *
  * @author Gavin King
  */

hibernate-core/src/main/java/org/hibernate/dialect/DB2Dialect.java

@@ -65,7 +65,7 @@ import jakarta.persistence.TemporalType;
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * An SQL dialect for DB2.
+ * A {@linkplain Dialect SQL dialect} for DB2.
  *
  * @author Gavin King
  */

hibernate-core/src/main/java/org/hibernate/dialect/DerbyDialect.java

@@ -76,7 +76,7 @@ import static org.hibernate.query.sqm.produce.function.StandardFunctionReturnTyp
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * Hibernate Dialect for Apache Derby / Cloudscape 10
+ * A {@linkplain Dialect SQL dialect} for Apache Derby.
  *
  * @author Simon Johnston
  * @author Gavin King

hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java

@@ -176,16 +176,37 @@ import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTime;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTimestampWithMicros;
 
 /**
- * Represents a dialect of SQL implemented by a particular RDBMS. Subclasses
- * implement Hibernate compatibility with different database platforms.
+ * Represents a dialect of SQL implemented by a particular RDBMS. Every
+ * subclass of this class implements support for a certain database
+ * platform. For example, {@link PostgreSQLDialect} implements support
+ * for PostgreSQL, and {@link MySQLDialect} implements support for MySQL.
  * <p>
- * Subclasses must provide a public constructor that registers a set of type
- * mappings from JDBC type codes to database native type names, along with
- * default Hibernate properties. This constructor may have no parameters, or
- * it may have a single parameter of type
- * {@link org.hibernate.engine.jdbc.dialect.spi.DialectResolutionInfo}.
+ * A subclass must provide a public constructor with a single parameter
+ * of type {@link DialectResolutionInfo}. Alternatively, for purposes of
+ * backward compatibility with older versions of Hibernate, a constructor
+ * with no parameters is also allowed.
  * <p>
- * Subclasses should be immutable.
+ * Almost every subclass must, as a bare minimum, override at least:
+ * <ul>
+ *     <li>{@link #columnType(int)} to define a mapping from JDBC
+ *     {@linkplain Types type codes} to database column types, and
+ *     <li>{@link #initializeFunctionRegistry(QueryEngine)} to register
+ *     mappings for standard HQL functions with the
+ *     {@link org.hibernate.query.sqm.function.SqmFunctionRegistry}.
+ * </ul>
+ * A subclass representing a dialect of SQL which deviates significantly
+ * from ANSI SQL will certainly override many additional operations.
+ * <p>
+ * Subclasses should be threadsafe and immutable.
+ * <p>
+ * Since Hibernate 6, a single subclass of {@code Dialect} represents all
+ * releases of a given product-specific SQL dialect. The version of the
+ * database is exposed at runtime via the {@link DialectResolutionInfo}
+ * passed to the constructor, and by the {@link #getVersion()} property.
+ * <p>
+ * Programs using Hibernate should migrate away from the use of versioned
+ * dialect classes like, for example, {@link PostgreSQL95Dialect}. These
+ * classes are now deprecated and will be removed in a future release.
  *
  * @author Gavin King, David Channon
  */

hibernate-core/src/main/java/org/hibernate/dialect/H2Dialect.java

@@ -69,7 +69,7 @@ import static org.hibernate.query.TemporalUnit.SECOND;
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * A dialect compatible with the H2 database.
+ * A {@linkplain Dialect SQL dialect} for H2.
  *
  * @author Thomas Mueller
  */
@@ -82,7 +82,6 @@ public class H2Dialect extends Dialect {
 	private final boolean cascadeConstraints;
 	private final boolean useLocalTime;
 
-	private final boolean supportsTuplesInSubqueries;
 	private final SequenceInformationExtractor sequenceInformationExtractor;
 	private final String querySequenceString;
 
@@ -107,7 +106,7 @@ public class H2Dialect extends Dialect {
 			LOG.unsupportedMultiTableBulkHqlJpaql( version.getMajor(), version.getMinor(), version.getMicro() );
 		}
 
-		supportsTuplesInSubqueries = version.isSameOrAfter( 1, 4, 198 );
+//		supportsTuplesInSubqueries = version.isSameOrAfter( 1, 4, 198 );
 
 		// Prior to 1.4.200 there was no support for 'current value for sequence_name'
 		// After 2.0.202 there is no support for 'sequence_name.nextval' and 'sequence_name.currval'
@@ -473,20 +472,20 @@ public class H2Dialect extends Dialect {
 
 	private static final ViolatedConstraintNameExtractor EXTRACTOR =
 			new TemplatedViolatedConstraintNameExtractor( sqle -> {
-				String constraintName = null;
 				// 23000: Check constraint violation: {0}
 				// 23001: Unique index or primary key violation: {0}
 				if ( sqle.getSQLState().startsWith( "23" ) ) {
 					final String message = sqle.getMessage();
 					final int idx = message.indexOf( "violation: " );
 					if ( idx > 0 ) {
-						constraintName = message.substring( idx + "violation: ".length() );
-					}
-					if ( sqle.getSQLState().equals( "23506" ) ) {
-						constraintName = constraintName.substring( 1, constraintName.indexOf( ":" ) );
+						String constraintName = message.substring( idx + "violation: ".length() );
+						if ( sqle.getSQLState().equals( "23506" ) ) {
+							constraintName = constraintName.substring( 1, constraintName.indexOf( ":" ) );
+						}
+						return constraintName;
 					}
 				}
-				return constraintName;
+				return null;
 			} );
 
 	@Override

hibernate-core/src/main/java/org/hibernate/dialect/HSQLDialect.java

@@ -79,7 +79,7 @@ import static org.hibernate.type.SqlTypes.NCLOB;
 import static org.hibernate.type.SqlTypes.NUMERIC;
 
 /**
- * An SQL dialect compatible with HyperSQL (HSQLDB) version 1.8 and above.
+ * A {@linkplain Dialect SQL dialect} for HSQLDB (HyperSQL) 1.8 and above.
  *
  * @author Christoph Sturm
  * @author Phillip Baird

hibernate-core/src/main/java/org/hibernate/dialect/MariaDBDialect.java

@@ -27,7 +27,7 @@ import org.hibernate.tool.schema.extract.spi.SequenceInformationExtractor;
 import org.hibernate.type.StandardBasicTypes;
 
 /**
- * SQL dialect for MariaDB
+ * A {@linkplain Dialect SQL dialect} for MariaDB
  *
  * @author Vlad Mihalcea
  * @author Gavin King

hibernate-core/src/main/java/org/hibernate/dialect/MySQLDialect.java

@@ -81,7 +81,7 @@ import static org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtract
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * An SQL dialect for MySQL (prior to 5.x).
+ * A {@linkplain Dialect SQL dialect} for MySQL 5 and above.
  *
  * @author Gavin King
  */

hibernate-core/src/main/java/org/hibernate/dialect/OracleDialect.java

@@ -95,7 +95,7 @@ import org.hibernate.query.sqm.produce.function.FunctionParameterType;
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * A dialect for Oracle 8i and above.
+ * A {@linkplain Dialect SQL dialect} for Oracle 8i and above.
  *
  * @author Steve Ebersole
  * @author Gavin King

hibernate-core/src/main/java/org/hibernate/dialect/PostgreSQLDialect.java

@@ -67,7 +67,6 @@ import org.hibernate.sql.ast.spi.StandardSqlAstTranslatorFactory;
 import org.hibernate.sql.ast.tree.Statement;
 import org.hibernate.sql.exec.spi.JdbcOperation;
 import org.hibernate.type.JavaObjectType;
-import org.hibernate.type.StandardBasicTypes;
 import org.hibernate.type.descriptor.java.PrimitiveByteArrayJavaTypeDescriptor;
 import org.hibernate.type.descriptor.jdbc.BlobJdbcType;
 import org.hibernate.type.descriptor.jdbc.ClobJdbcType;
@@ -85,14 +84,13 @@ import static org.hibernate.query.TemporalUnit.MONTH;
 import static org.hibernate.query.TemporalUnit.QUARTER;
 import static org.hibernate.query.TemporalUnit.YEAR;
 
-import org.hibernate.query.sqm.produce.function.FunctionParameterType;
 import static org.hibernate.type.SqlTypes.*;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsDate;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTime;
 import static org.hibernate.type.descriptor.DateTimeUtils.appendAsTimestampWithMicros;
 
 /**
- * An SQL dialect for Postgres 8 and above.
+ * A {@linkplain Dialect SQL dialect} for PostgreSQL 8 and above.
  *
  * @author Gavin King
  */

hibernate-core/src/main/java/org/hibernate/dialect/SpannerDialect.java

@@ -55,7 +55,7 @@ import static org.hibernate.dialect.SimpleDatabaseVersion.ZERO_VERSION;
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * Hibernate Dialect implementation for Cloud Spanner.
+ * A {@linkplain Dialect SQL dialect} for Cloud Spanner.
  *
  * @author Mike Eltsufin
  * @author Chengyuan Zhao
@@ -133,7 +133,8 @@ public class SpannerDialect extends Dialect {
 		return 2_621_440;
 	}
 
-	public int getMaxBytesLength() {
+	@Override
+	public int getMaxVarbinaryLength() {
 		//max is equivalent to 10_485_760
 		return 10_485_760;
 	}

hibernate-core/src/main/java/org/hibernate/dialect/SybaseASEDialect.java

@@ -46,8 +46,7 @@ import static org.hibernate.exception.spi.TemplatedViolatedConstraintNameExtract
 import static org.hibernate.type.SqlTypes.*;
 
 /**
- * Dialect for Sybase Adaptive Server Enterprise for
- * Sybase 11.9.2 and above.
+ * A {@linkplain Dialect SQL dialect} for Sybase Adaptive Server Enterprise 11.9 and above.
  */
 public class SybaseASEDialect extends SybaseDialect {
 
@@ -589,7 +588,6 @@ public class SybaseASEDialect extends SybaseDialect {
 	}
 
 	@Override
-	@SuppressWarnings("deprecation")
 	public String applyLocksToSql(String sql, LockOptions aliasedLockOptions, Map<String, String[]> keyColumnNames) {
 		//TODO: is this really correct?
 		return getVersion().isBefore( 15, 7 )

hibernate-core/src/main/java/org/hibernate/dialect/TiDBDialect.java

@@ -22,7 +22,7 @@ import org.hibernate.tool.schema.extract.internal.SequenceInformationExtractorTi
 import org.hibernate.tool.schema.extract.spi.SequenceInformationExtractor;
 
 /**
- * An SQL dialect for TiDB (prior to 5.x).
+ * A {@linkplain Dialect SQL dialect} for TiDB.
  *
  * @author Cong Wang
  */