Hibernate

Replacements

java.util.Date     => java.time.Instant
java.sql.Timestamp => java.time.Instant
java.sql.Date      => java.time.LocalDate
java.sql.Time      => java.time.LocalTime

The Instant class represents a moment on the timeline in UTC with a resolution of nanoseconds (up to nine (9) digits of a decimal fraction).All three java.time.Local… classes are all lacking any concept of time zone or offset-from-UTC.

Sequence Style

@Id
@Column(name = "code", length = 8)
//@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "page_sqn")
//@SequenceGenerator(name = "page_sqn", sequenceName = "page_sqn", initialValue = 60466176, allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "page_sqn")
@GenericGenerator(name  = "page_sqn", strategy = "org.chorke.academia.core.entity.Base36Style", parameters = {
    @Parameter(name = Base36Style.INITIAL_VALUE,   value = Base36Style.DIGIT_6_MIN),
    @Parameter(name = Base36Style.SEQUENCE_NAME,   value = "page_sqn"),
    @Parameter(name = Base36Style.ALLOCATION_SIZE, value = "1"),
})
private String code;

package org.chorke.academia.core.entity;

import java.io.Serializable;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.MappingException;
import org.hibernate.engine.spi.SharedSessionContractImplementor;
import org.hibernate.id.enhanced.SequenceStyleGenerator;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.type.Type;

public class Base36Style extends SequenceStyleGenerator {
    public static final String ALLOCATION_SIZE = INCREMENT_PARAM;
    public static final String SEQUENCE_NAME = SEQUENCE_PARAM;
    public static final String INITIAL_VALUE = INITIAL_PARAM;
    public static final int RADIX = 36;

    public static final String DIGIT_1_MIN = "0";
    public static final String DIGIT_2_MIN = "36";
    public static final String DIGIT_3_MIN = "1296";
    public static final String DIGIT_4_MIN = "46656";
    public static final String DIGIT_5_MIN = "1679616";
    public static final String DIGIT_6_MIN = "60466176";
    public static final String DIGIT_7_MIN = "2176782336";
    public static final String DIGIT_8_MIN = "78364164096";
    public static final String DIGIT_9_MIN = "2821109907456";
    public static final String DIGIT_X_MIN = "101559956668416";

    @Override
    public Serializable generate(SharedSessionContractImplementor session, Object object) throws HibernateException {
        Serializable nextval = super.generate(session, object);
        String base36 = Long.toString((long) nextval, RADIX);
        return base36.toUpperCase();
    }

    @Override
    public void configure(Type type, Properties params, ServiceRegistry serviceRegistry) throws MappingException {
        super.configure(type, params, serviceRegistry);
    }
}

Challenges

Database	Auto Increment	Sequence	Usable
DB2/LUW	✓	✓	✓
DB2/z	✓	✓	✓
PostgreSQL	✓	✓	✓
Derby	✕	✓	✓
Firebird	✕	✓	✓
H2	✓	✓	✓
HyperSQL	✓	✓	✓
INGRES	✓	✕	✕
Informix	✓	✓	✓
MariaDB	✓	✕	✕
MySQL	✓	✕	✕
Oracle	✕	✓	✓
Sql Server	✕	✓	✓
SQLite	✓	✕	✕
Sybase	✓	✕	✕
Sybase Anywhere	✓	✓	✓

References

Choosing between java.util.Date or java.sql.Date An Overview of Identifiers in Hibernate Immutable and NaturalId Annotations Custom Id Generator using Hibernate Convention for Database Tables Java Persistence/Inheritance How to generate Custom Id NaturalId Example Tutorial Natural IDs in Spring Boot EclipseLink

Never use the TABLE identifier generator Custom Sequence Based ID Generator Create Sequence Supported Database Auto Increment Supported Database JPA Primary Key Prefix DBUnit Locale