Merge pull request #8125 from eugenp/revert-8119-BAEL-3275-2

Revert "BAEL-3275: Using blocking queue for pub-sub"

persistence-modules/java-jpa/README.md

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+## JPA in Java
+
+This module contains articles about the Java Persistence API (JPA) in Java.
+
+### Relevant Articles
+
+- [A Guide to SqlResultSetMapping](https://www.baeldung.com/jpa-sql-resultset-mapping)
+- [A Guide to Stored Procedures with JPA](https://www.baeldung.com/jpa-stored-procedures)
+- [Fixing the JPA error “java.lang.String cannot be cast to Ljava.lang.String;”](https://www.baeldung.com/jpa-error-java-lang-string-cannot-be-cast)
+- [JPA Entity Graph](https://www.baeldung.com/jpa-entity-graph)
+- [JPA 2.2 Support for Java 8 Date/Time Types](https://www.baeldung.com/jpa-java-time)
+- [Converting Between LocalDate and SQL Date](https://www.baeldung.com/java-convert-localdate-sql-date)
+- [Composite Primary Keys in JPA](https://www.baeldung.com/jpa-composite-primary-keys)
+- [Defining JPA Entities](https://www.baeldung.com/jpa-entities)
+- [JPA @Basic Annotation](https://www.baeldung.com/jpa-basic-annotation)
+- [Persisting Enums in JPA](https://www.baeldung.com/jpa-persisting-enums-in-jpa)
+- More articles: [[next -->]](/java-jpa-2)

persistence-modules/java-jpa/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>java-jpa</artifactId>
+    <name>java-jpa</name>
+
+    <parent>
+        <artifactId>parent-modules</artifactId>
+        <groupId>com.baeldung</groupId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../../pom.xml</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.hibernate</groupId>
+            <artifactId>hibernate-core</artifactId>
+            <version>${hibernate.version}</version>
+        </dependency>
+		<dependency>
+			<groupId>org.hibernate</groupId>
+			<artifactId>hibernate-jpamodelgen</artifactId>
+			<version>${hibernate.version}</version>
+		</dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <version>${h2.version}</version>
+        </dependency>
+
+        <!--Compile time JPA API-->
+        <dependency>
+            <groupId>javax.persistence</groupId>
+            <artifactId>javax.persistence-api</artifactId>
+            <version>${javax.persistence-api.version}</version>
+        </dependency>
+
+        <!--Runtime JPA implementation-->
+        <dependency>
+            <groupId>org.eclipse.persistence</groupId>
+            <artifactId>eclipselink</artifactId>
+            <version>${eclipselink.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+            <version>${postgres.version}</version>
+            <scope>runtime</scope>
+        </dependency>
+    </dependencies>
+
+	<build>
+		<plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${maven-compiler-plugin.version}</version>
+                <configuration>
+                    <compilerArgument>-proc:none</compilerArgument>
+                </configuration>
+            </plugin>
+			<plugin>
+				<groupId>org.bsc.maven</groupId>
+				<artifactId>maven-processor-plugin</artifactId>
+				<version>${maven-processor-plugin.version}</version>
+				<executions>
+					<execution>
+						<id>process</id>
+						<goals>
+							<goal>process</goal>
+						</goals>
+						<phase>generate-sources</phase>
+						<configuration>
+							<outputDirectory>target/metamodel</outputDirectory>
+							<processors>
+								<processor>org.hibernate.jpamodelgen.JPAMetaModelEntityProcessor</processor>
+							</processors>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+
+			<plugin>
+				<groupId>org.codehaus.mojo</groupId>
+				<artifactId>build-helper-maven-plugin</artifactId>
+				<version>${build-helper-maven-plugin.version}</version>
+				<executions>
+					<execution>
+						<id>add-source</id>
+						<phase>generate-sources</phase>
+						<goals>
+							<goal>add-source</goal>
+						</goals>
+						<configuration>
+							<sources>
+								<source>target/metamodel</source>
+							</sources>
+						</configuration>
+					</execution>
+				</executions>
+			</plugin>
+		</plugins>
+	</build>
+
+    <properties>
+        <hibernate.version>5.4.0.Final</hibernate.version>
+        <eclipselink.version>2.7.4-RC1</eclipselink.version>
+        <postgres.version>42.2.5</postgres.version>
+        <javax.persistence-api.version>2.2</javax.persistence-api.version>
+        <maven-processor-plugin.version>3.3.3</maven-processor-plugin.version>
+        <build-helper-maven-plugin.version>3.0.0</build-helper-maven-plugin.version>
+    </properties>
+
+</project>

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/basicannotation/Course.java

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+package com.baeldung.jpa.basicannotation;
+
+import javax.persistence.Basic;
+import javax.persistence.Entity;
+import javax.persistence.FetchType;
+import javax.persistence.Id;
+
+@Entity
+public class Course {
+
+    @Id
+    private int id;
+
+    @Basic(optional = false, fetch = FetchType.LAZY)
+    private String name;
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}
+

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/convertdates/LocalDateConverter.java

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+package com.baeldung.jpa.convertdates;
+
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+import java.sql.Date;
+import java.time.LocalDate;
+import java.util.Optional;
+
+@Converter(autoApply = true)
+public class LocalDateConverter implements AttributeConverter<LocalDate, Date> {
+
+    @Override
+    public Date convertToDatabaseColumn(LocalDate localDate) {
+        return Optional.ofNullable(localDate)
+                .map(Date::valueOf)
+                .orElse(null);
+    }
+
+    @Override
+    public LocalDate convertToEntityAttribute(Date date) {
+        return Optional.ofNullable(date)
+                .map(Date::toLocalDate)
+                .orElse(null);
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/datetime/DateTimeEntityRepository.java

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+package com.baeldung.jpa.datetime;
+
+import javax.persistence.EntityManager;
+import javax.persistence.EntityManagerFactory;
+import javax.persistence.Persistence;
+import java.sql.Date;
+import java.sql.Time;
+import java.sql.Timestamp;
+import java.time.*;
+import java.util.Calendar;
+
+public class DateTimeEntityRepository {
+    private EntityManagerFactory emf = null;
+
+    public DateTimeEntityRepository() {
+        emf = Persistence.createEntityManagerFactory("java8-datetime-postgresql");
+    }
+
+    public JPA22DateTimeEntity find(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        JPA22DateTimeEntity dateTimeTypes = entityManager.find(JPA22DateTimeEntity.class, id);
+
+        entityManager.close();
+        return dateTimeTypes;
+    }
+
+    public void save(Long id) {
+        JPA22DateTimeEntity dateTimeTypes = new JPA22DateTimeEntity();
+        dateTimeTypes.setId(id);
+
+        //java.sql types: date/time
+        dateTimeTypes.setSqlTime(Time.valueOf(LocalTime.now()));
+        dateTimeTypes.setSqlDate(Date.valueOf(LocalDate.now()));
+        dateTimeTypes.setSqlTimestamp(Timestamp.valueOf(LocalDateTime.now()));
+
+        //java.util types: date/calendar
+        java.util.Date date = new java.util.Date();
+        dateTimeTypes.setUtilTime(date);
+        dateTimeTypes.setUtilDate(date);
+        dateTimeTypes.setUtilTimestamp(date);
+
+        //Calendar
+        Calendar calendar = Calendar.getInstance();
+        dateTimeTypes.setCalendarTime(calendar);
+        dateTimeTypes.setCalendarDate(calendar);
+        dateTimeTypes.setCalendarTimestamp(calendar);
+
+        //java.time types
+        dateTimeTypes.setLocalTime(LocalTime.now());
+        dateTimeTypes.setLocalDate(LocalDate.now());
+        dateTimeTypes.setLocalDateTime(LocalDateTime.now());
+
+        //java.time types with offset
+        dateTimeTypes.setOffsetTime(OffsetTime.now());
+        dateTimeTypes.setOffsetDateTime(OffsetDateTime.now());
+
+        EntityManager entityManager = emf.createEntityManager();
+        entityManager.getTransaction().begin();
+        entityManager.persist(dateTimeTypes);
+        entityManager.getTransaction().commit();
+        entityManager.close();
+    }
+
+    public void clean() {
+        emf.close();
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/datetime/JPA22DateTimeEntity.java

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+package com.baeldung.jpa.datetime;
+
+import javax.persistence.*;
+import java.sql.Date;
+import java.sql.Time;
+import java.sql.Timestamp;
+import java.time.*;
+import java.util.Calendar;
+
+@Entity
+public class JPA22DateTimeEntity {
+
+    @Id
+    private Long id;
+
+    //java.sql types
+    private Time sqlTime;
+    private Date sqlDate;
+    private Timestamp sqlTimestamp;
+
+    //java.util types
+    @Temporal(TemporalType.TIME)
+    private java.util.Date utilTime;
+
+    @Temporal(TemporalType.DATE)
+    private java.util.Date utilDate;
+
+    @Temporal(TemporalType.TIMESTAMP)
+    private java.util.Date utilTimestamp;
+
+    //Calendar
+    @Temporal(TemporalType.TIME)
+    private Calendar calendarTime;
+
+    @Temporal(TemporalType.DATE)
+    private Calendar calendarDate;
+
+    @Temporal(TemporalType.TIMESTAMP)
+    private Calendar calendarTimestamp;
+
+    // java.time types
+    @Column(name = "local_time", columnDefinition = "TIME")
+    private LocalTime localTime;
+
+    @Column(name = "local_date", columnDefinition = "DATE")
+    private LocalDate localDate;
+
+    @Column(name = "local_date_time", columnDefinition = "TIMESTAMP")
+    private LocalDateTime localDateTime;
+
+    @Column(name = "offset_time", columnDefinition = "TIME WITH TIME ZONE")
+    private OffsetTime offsetTime;
+
+    @Column(name = "offset_date_time", columnDefinition = "TIMESTAMP WITH TIME ZONE")
+    private OffsetDateTime offsetDateTime;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Time getSqlTime() {
+        return sqlTime;
+    }
+
+    public void setSqlTime(Time sqlTime) {
+        this.sqlTime = sqlTime;
+    }
+
+    public Date getSqlDate() {
+        return sqlDate;
+    }
+
+    public void setSqlDate(Date sqlDate) {
+        this.sqlDate = sqlDate;
+    }
+
+    public Timestamp getSqlTimestamp() {
+        return sqlTimestamp;
+    }
+
+    public void setSqlTimestamp(Timestamp sqlTimestamp) {
+        this.sqlTimestamp = sqlTimestamp;
+    }
+
+    public java.util.Date getUtilTime() {
+        return utilTime;
+    }
+
+    public void setUtilTime(java.util.Date utilTime) {
+        this.utilTime = utilTime;
+    }
+
+    public java.util.Date getUtilDate() {
+        return utilDate;
+    }
+
+    public void setUtilDate(java.util.Date utilDate) {
+        this.utilDate = utilDate;
+    }
+
+    public java.util.Date getUtilTimestamp() {
+        return utilTimestamp;
+    }
+
+    public void setUtilTimestamp(java.util.Date utilTimestamp) {
+        this.utilTimestamp = utilTimestamp;
+    }
+
+    public Calendar getCalendarTime() {
+        return calendarTime;
+    }
+
+    public void setCalendarTime(Calendar calendarTime) {
+        this.calendarTime = calendarTime;
+    }
+
+    public Calendar getCalendarDate() {
+        return calendarDate;
+    }
+
+    public void setCalendarDate(Calendar calendarDate) {
+        this.calendarDate = calendarDate;
+    }
+
+    public Calendar getCalendarTimestamp() {
+        return calendarTimestamp;
+    }
+
+    public void setCalendarTimestamp(Calendar calendarTimestamp) {
+        this.calendarTimestamp = calendarTimestamp;
+    }
+
+    public LocalTime getLocalTime() {
+        return localTime;
+    }
+
+    public void setLocalTime(LocalTime localTime) {
+        this.localTime = localTime;
+    }
+
+    public LocalDate getLocalDate() {
+        return localDate;
+    }
+
+    public void setLocalDate(LocalDate localDate) {
+        this.localDate = localDate;
+    }
+
+    public LocalDateTime getLocalDateTime() {
+        return localDateTime;
+    }
+
+    public void setLocalDateTime(LocalDateTime localDateTime) {
+        this.localDateTime = localDateTime;
+    }
+
+    public OffsetTime getOffsetTime() {
+        return offsetTime;
+    }
+
+    public void setOffsetTime(OffsetTime offsetTime) {
+        this.offsetTime = offsetTime;
+    }
+
+    public OffsetDateTime getOffsetDateTime() {
+        return offsetDateTime;
+    }
+
+    public void setOffsetDateTime(OffsetDateTime offsetDateTime) {
+        this.offsetDateTime = offsetDateTime;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/datetime/MainApp.java

@@ -0,0 +1,18 @@
+package com.baeldung.jpa.datetime;
+
+public class MainApp {
+
+    public static void main(String... args) {
+
+        DateTimeEntityRepository dateTimeEntityRepository = new DateTimeEntityRepository();
+
+        //Persist
+        dateTimeEntityRepository.save(100L);
+
+        //Find
+        JPA22DateTimeEntity dateTimeEntity = dateTimeEntityRepository.find(100L);
+
+        dateTimeEntityRepository.clean();
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entity/Gender.java

@@ -0,0 +1,6 @@
+package com.baeldung.jpa.entity;
+
+public enum Gender {
+	MALE,
+	FEMALE
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entity/Student.java

@@ -0,0 +1,73 @@
+package com.baeldung.jpa.entity;
+
+import java.util.Date;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.EnumType;
+import javax.persistence.Enumerated;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.Table;
+import javax.persistence.Temporal;
+import javax.persistence.TemporalType;
+import javax.persistence.Transient;
+
+@Entity
+@Table(name="STUDENT")
+public class Student {
+
+	@Id
+	@GeneratedValue(strategy = GenerationType.AUTO)
+	private Long id;
+	@Column(name = "STUDENT_NAME", length = 50, nullable = false, unique = false)
+	private String name;
+	@Transient
+	private Integer age;
+	@Temporal(TemporalType.DATE)
+	private Date birthDate;
+	@Enumerated(EnumType.STRING)
+	private Gender gender;
+
+	public Long getId() {
+		return id;
+	}
+
+	public void setId(Long id) {
+		this.id = id;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+	public Integer getAge() {
+		return age;
+	}
+
+	public void setAge(Integer age) {
+		this.age = age;
+	}
+
+	public Date getBirthDate() {
+		return birthDate;
+	}
+
+	public void setBirthDate(Date birthDate) {
+		this.birthDate = birthDate;
+	}
+
+	public Gender getGender() {
+		return gender;
+	}
+
+	public void setGender(Gender gender) {
+		this.gender = gender;
+	}
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/MainApp.java

@@ -0,0 +1,26 @@
+package com.baeldung.jpa.entitygraph;
+
+import com.baeldung.jpa.entitygraph.model.Post;
+import com.baeldung.jpa.entitygraph.repo.PostRepository;
+
+public class MainApp {
+
+    public static void main(String... args) {
+        Long postId = 1L;
+        Post post = null;
+        PostRepository postRepository = new PostRepository();
+
+        //Using EntityManager.find().
+        post = postRepository.find(postId);
+        post = postRepository.findWithEntityGraph(postId);
+        post = postRepository.findWithEntityGraph2(postId);
+
+        //Using JPQL: Query and TypedQuery
+        post = postRepository.findUsingJpql(postId);
+
+        //Using Criteria API
+        post = postRepository.findUsingCriteria(postId);
+
+        postRepository.clean();
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/Comment.java

@@ -0,0 +1,63 @@
+package com.baeldung.jpa.entitygraph.model;
+
+import javax.persistence.*;
+
+@Entity
+public class Comment {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String reply;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn
+    private Post post;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn
+    private User user;
+    //...
+
+    public Comment() {
+    }
+
+    public Comment(String reply, Post post, User user) {
+        this.reply = reply;
+        this.post = post;
+        this.user = user;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getReply() {
+        return reply;
+    }
+
+    public void setReply(String reply) {
+        this.reply = reply;
+    }
+
+    public Post getPost() {
+        return post;
+    }
+
+    public void setPost(Post post) {
+        this.post = post;
+    }
+
+    public User getUser() {
+        return user;
+    }
+
+    public void setUser(User user) {
+        this.user = user;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/Post.java

@@ -0,0 +1,86 @@
+package com.baeldung.jpa.entitygraph.model;
+
+import javax.persistence.*;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.List;
+
+@NamedEntityGraph(
+        name = "post-entity-graph",
+        attributeNodes = {
+                @NamedAttributeNode("subject"),
+                @NamedAttributeNode("user"),
+                @NamedAttributeNode("comments"),
+        }
+)
+@NamedEntityGraph(
+        name = "post-entity-graph-with-comment-users",
+        attributeNodes = {
+                @NamedAttributeNode("subject"),
+                @NamedAttributeNode("user"),
+                @NamedAttributeNode(value = "comments", subgraph = "comments-subgraph"),
+        },
+        subgraphs = {
+                @NamedSubgraph(
+                        name = "comments-subgraph",
+                        attributeNodes = {
+                                @NamedAttributeNode("user")
+                        }
+                )
+        }
+)
+@Entity
+public class Post {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    private String subject;
+    @OneToMany(mappedBy = "post")
+    private List<Comment> comments = new ArrayList<>();
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn
+    private User user;
+    //...
+
+    public Post() {
+    }
+
+    public Post(String subject, User user) {
+        this.subject = subject;
+        this.user = user;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getSubject() {
+        return subject;
+    }
+
+    public void setSubject(String subject) {
+        this.subject = subject;
+    }
+
+    public List<Comment> getComments() {
+        return comments;
+    }
+
+    public void setComments(List<Comment> comments) {
+        this.comments = comments;
+    }
+
+    public User getUser() {
+        return user;
+    }
+
+    public void setUser(User user) {
+        this.user = user;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/model/User.java

@@ -0,0 +1,48 @@
+package com.baeldung.jpa.entitygraph.model;
+
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+
+@Entity
+public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+    private String name;
+    private String email;
+
+    //...
+
+    public User() {
+    }
+
+    public User(String email) {
+        this.email = email;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/entitygraph/repo/PostRepository.java

@@ -0,0 +1,93 @@
+package com.baeldung.jpa.entitygraph.repo;
+
+import com.baeldung.jpa.entitygraph.model.Post;
+
+import javax.persistence.*;
+import javax.persistence.criteria.CriteriaBuilder;
+import javax.persistence.criteria.CriteriaQuery;
+import javax.persistence.criteria.Root;
+import java.util.HashMap;
+import java.util.Map;
+
+public class PostRepository {
+    private EntityManagerFactory emf = null;
+
+
+    public PostRepository() {
+        Map properties = new HashMap();
+        properties.put("hibernate.show_sql", "true");
+        properties.put("hibernate.format_sql", "true");
+        emf = Persistence.createEntityManagerFactory("entity-graph-pu", properties);
+    }
+
+    public Post find(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        Post post = entityManager.find(Post.class, id);
+
+        entityManager.close();
+        return post;
+    }
+
+    public Post findWithEntityGraph(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph");
+        Map<String, Object> properties = new HashMap<>();
+        properties.put("javax.persistence.fetchgraph", entityGraph);
+        Post post = entityManager.find(Post.class, id, properties);
+
+        entityManager.close();
+        return post;
+    }
+
+    public Post findWithEntityGraph2(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        EntityGraph<Post> entityGraph = entityManager.createEntityGraph(Post.class);
+        entityGraph.addAttributeNodes("subject");
+        entityGraph.addAttributeNodes("user");
+        entityGraph.addSubgraph("comments")
+                .addAttributeNodes("user");
+
+        Map<String, Object> properties = new HashMap<>();
+        properties.put("javax.persistence.fetchgraph", entityGraph);
+        Post post = entityManager.find(Post.class, id, properties);
+
+        entityManager.close();
+        return post;
+    }
+
+    public Post findUsingJpql(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph-with-comment-users");
+        Post post = entityManager.createQuery("Select p from Post p where p.id=:id", Post.class)
+                .setParameter("id", id)
+                .setHint("javax.persistence.fetchgraph", entityGraph)
+                .getSingleResult();
+
+        entityManager.close();
+        return post;
+    }
+
+    public Post findUsingCriteria(Long id) {
+        EntityManager entityManager = emf.createEntityManager();
+
+        EntityGraph entityGraph = entityManager.getEntityGraph("post-entity-graph-with-comment-users");
+        CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
+        CriteriaQuery<Post> criteriaQuery = criteriaBuilder.createQuery(Post.class);
+        Root<Post> root = criteriaQuery.from(Post.class);
+        criteriaQuery.where(criteriaBuilder.equal(root.<Long>get("id"), id));
+        TypedQuery<Post> typedQuery = entityManager.createQuery(criteriaQuery);
+        typedQuery.setHint("javax.persistence.loadgraph", entityGraph);
+        Post post = typedQuery.getSingleResult();
+
+        entityManager.close();
+        return post;
+    }
+
+    public void clean() {
+        emf.close();
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/Article.java

@@ -0,0 +1,91 @@
+package com.baeldung.jpa.enums;
+
+import javax.persistence.*;
+
+@Entity
+public class Article {
+
+    @Id
+    private int id;
+
+    private String title;
+
+    @Enumerated(EnumType.ORDINAL)
+    private Status status;
+
+    @Enumerated(EnumType.STRING)
+    private Type type;
+
+    @Basic
+    private int priorityValue;
+
+    @Transient
+    private Priority priority;
+
+    private Category category;
+
+    public Article() {
+    }
+
+    @PostLoad
+    void fillTransient() {
+        if (priorityValue > 0) {
+            this.priority = Priority.of(priorityValue);
+        }
+    }
+
+    @PrePersist
+    void fillPersistent() {
+        if (priority != null) {
+            this.priorityValue = priority.getPriority();
+        }
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public Status getStatus() {
+        return status;
+    }
+
+    public void setStatus(Status status) {
+        this.status = status;
+    }
+
+    public Type getType() {
+        return type;
+    }
+
+    public void setType(Type type) {
+        this.type = type;
+    }
+
+    public Priority getPriority() {
+        return priority;
+    }
+
+    public void setPriority(Priority priority) {
+        this.priority = priority;
+    }
+
+    public Category getCategory() {
+        return category;
+    }
+
+    public void setCategory(Category category) {
+        this.category = category;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/Category.java

@@ -0,0 +1,17 @@
+package com.baeldung.jpa.enums;
+
+import java.util.stream.Stream;
+
+public enum Category {
+    SPORT("S"), MUSIC("M"), TECHNOLOGY("T");
+
+    private String code;
+
+    Category(String code) {
+        this.code = code;
+    }
+
+    public String getCode() {
+        return code;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/CategoryConverter.java

@@ -0,0 +1,28 @@
+package com.baeldung.jpa.enums;
+
+import javax.persistence.AttributeConverter;
+import javax.persistence.Converter;
+import java.util.stream.Stream;
+
+@Converter(autoApply = true)
+public class CategoryConverter implements AttributeConverter<Category, String> {
+    @Override
+    public String convertToDatabaseColumn(Category category) {
+        if (category == null) {
+            return null;
+        }
+        return category.getCode();
+    }
+
+    @Override
+    public Category convertToEntityAttribute(final String code) {
+        if (code == null) {
+            return null;
+        }
+
+        return Stream.of(Category.values())
+                .filter(c -> c.getCode().equals(code))
+                .findFirst()
+                .orElseThrow(IllegalArgumentException::new);
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/Priority.java

@@ -0,0 +1,24 @@
+package com.baeldung.jpa.enums;
+
+import java.util.stream.Stream;
+
+public enum Priority {
+    LOW(100), MEDIUM(200), HIGH(300);
+
+    private int priority;
+
+    private Priority(int priority) {
+        this.priority = priority;
+    }
+
+    public int getPriority() {
+        return priority;
+    }
+
+    public static Priority of(int priority) {
+        return Stream.of(Priority.values())
+                .filter(p -> p.getPriority() == priority)
+                .findFirst()
+                .orElseThrow(IllegalArgumentException::new);
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/Status.java

@@ -0,0 +1,5 @@
+package com.baeldung.jpa.enums;
+
+public enum Status {
+    OPEN, REVIEW, APPROVED, REJECTED;
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/enums/Type.java

@@ -0,0 +1,5 @@
+package com.baeldung.jpa.enums;
+
+enum Type {
+    INTERNAL, EXTERNAL;
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/model/Car.java

@@ -0,0 +1,60 @@
+package com.baeldung.jpa.model;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.NamedStoredProcedureQueries;
+import javax.persistence.NamedStoredProcedureQuery;
+import javax.persistence.ParameterMode;
+import javax.persistence.StoredProcedureParameter;
+import javax.persistence.Table;
+
+@Entity
+@Table(name = "CAR")
+@NamedStoredProcedureQueries({
+        @NamedStoredProcedureQuery(name = "findByYearProcedure", procedureName = "FIND_CAR_BY_YEAR", resultClasses = { Car.class }, parameters = { @StoredProcedureParameter(name = "p_year", type = Integer.class, mode = ParameterMode.IN) }) })
+public class Car {
+
+    private long id;
+    private String model;
+    private Integer year;
+
+    public Car(final String model, final Integer year) {
+        this.model = model;
+        this.year = year;
+    }
+
+    public Car() {
+    }
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "ID", unique = true, nullable = false, scale = 0)
+    public long getId() {
+        return id;
+    }
+
+    public void setId(final long id) {
+        this.id = id;
+    }
+
+    @Column(name = "MODEL")
+    public String getModel() {
+        return model;
+    }
+
+    public void setModel(final String model) {
+        this.model = model;
+    }
+
+    @Column(name = "YEAR")
+    public Integer getYear() {
+        return year;
+    }
+
+    public void setYear(final Integer year) {
+        this.year = year;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/model/QueryParameter.java

@@ -0,0 +1,28 @@
+package com.baeldung.jpa.model;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class QueryParameter {
+
+    private Map<String, Object> parameters = null;
+
+    private QueryParameter(final String name, final Object value) {
+        this.parameters = new HashMap<>();
+        this.parameters.put(name, value);
+    }
+
+    public static QueryParameter with(final String name, final Object value) {
+        return new QueryParameter(name, value);
+    }
+
+    public QueryParameter and(final String name, final Object value) {
+        this.parameters.put(name, value);
+        return this;
+    }
+
+    public Map<String, Object> parameters() {
+        return this.parameters;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/primarykeys/Account.java

@@ -0,0 +1,43 @@
+package com.baeldung.jpa.primarykeys;
+
+import javax.persistence.Entity;
+import javax.persistence.Id;
+import javax.persistence.IdClass;
+
+@Entity
+@IdClass(AccountId.class)
+public class Account {
+
+    @Id
+    private String accountNumber;
+
+    @Id
+    private String accountType;
+
+    private String description;
+
+    public String getAccountNumber() {
+        return accountNumber;
+    }
+
+    public void setAccountNumber(String accountNumber) {
+        this.accountNumber = accountNumber;
+    }
+
+    public String getAccountType() {
+        return accountType;
+    }
+
+    public void setAccountType(String accountType) {
+        this.accountType = accountType;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/primarykeys/AccountId.java

@@ -0,0 +1,52 @@
+package com.baeldung.jpa.primarykeys;
+
+import java.io.Serializable;
+
+public class AccountId implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private String accountNumber;
+    private String accountType;
+
+    public AccountId() {
+
+    }
+
+    public AccountId(String accountNumber, String accountType) {
+        this.accountNumber = accountNumber;
+        this.accountType = accountType;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((accountNumber == null) ? 0 : accountNumber.hashCode());
+        result = prime * result + ((accountType == null) ? 0 : accountType.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        AccountId other = (AccountId) obj;
+        if (accountNumber == null) {
+            if (other.accountNumber != null)
+                return false;
+        } else if (!accountNumber.equals(other.accountNumber))
+            return false;
+        if (accountType == null) {
+            if (other.accountType != null)
+                return false;
+        } else if (!accountType.equals(other.accountType))
+            return false;
+        return true;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/primarykeys/Book.java

@@ -0,0 +1,34 @@
+package com.baeldung.jpa.primarykeys;
+
+import javax.persistence.EmbeddedId;
+import javax.persistence.Entity;
+
+@Entity
+public class Book {
+
+    @EmbeddedId
+    private BookId bookId;
+
+    private String description;
+
+    public Book() {
+
+    }
+
+    public Book(BookId bookId) {
+        this.bookId = bookId;
+    }
+
+    public BookId getBookId() {
+        return bookId;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/primarykeys/BookId.java

@@ -0,0 +1,62 @@
+package com.baeldung.jpa.primarykeys;
+
+import java.io.Serializable;
+
+import javax.persistence.Embeddable;
+
+@Embeddable
+public class BookId implements Serializable {
+
+    private static final long serialVersionUID = 1L;
+    private String title;
+    private String language;
+
+    public BookId() {
+
+    }
+
+    public BookId(String title, String language) {
+        this.title = title;
+        this.language = language;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public String getLanguage() {
+        return language;
+    }
+
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((language == null) ? 0 : language.hashCode());
+        result = prime * result + ((title == null) ? 0 : title.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        BookId other = (BookId) obj;
+        if (language == null) {
+            if (other.language != null)
+                return false;
+        } else if (!language.equals(other.language))
+            return false;
+        if (title == null) {
+            if (other.title != null)
+                return false;
+        } else if (!title.equals(other.title))
+            return false;
+        return true;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/sqlresultsetmapping/Employee.java

@@ -0,0 +1,43 @@
+package com.baeldung.jpa.sqlresultsetmapping;
+
+import javax.persistence.*;
+
+
+@SqlResultSetMapping(
+        name="EmployeeResult",
+        entities={
+                @EntityResult(
+                        entityClass = com.baeldung.jpa.sqlresultsetmapping.Employee.class,
+                        fields={@FieldResult(name="id",column="employeeNumber"),
+                                 @FieldResult(name="name", column="name")}
+                )
+        }
+)
+@NamedNativeQuery(
+        name="Employees",
+        query="SELECT id as employeeNumber, name FROM EMPLOYEE",
+        resultSetMapping = "EmployeeResult"
+)
+@Entity
+public class Employee {
+
+    @Id
+    private Long id;
+    private String name;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/sqlresultsetmapping/ScheduledDay.java

@@ -0,0 +1,58 @@
+package com.baeldung.jpa.sqlresultsetmapping;
+
+import javax.persistence.*;
+
+@SqlResultSetMappings(value = {
+    @SqlResultSetMapping(name = "ScheduleResult",
+        classes = { @ConstructorResult(targetClass = com.baeldung.jpa.sqlresultsetmapping.ScheduledDay.class,
+        columns = { @ColumnResult(name = "id", type = Long.class),
+                    @ColumnResult(name = "employeeId", type = Long.class),
+                    @ColumnResult(name = "dayOfWeek") }) }),
+    @SqlResultSetMapping(name = "FridayEmployeeResult",
+                         columns = { @ColumnResult(name = "employeeId") }),
+    @SqlResultSetMapping(name = "EmployeeScheduleResults",
+                         entities = { @EntityResult(entityClass = com.baeldung.jpa.sqlresultsetmapping.Employee.class),
+                                      @EntityResult(entityClass = com.baeldung.jpa.sqlresultsetmapping.ScheduledDay.class)
+    }) })
+@NamedNativeQuery(name = "FridayEmployees",
+        query = "SELECT employeeId FROM schedule_days WHERE dayOfWeek = 'FRIDAY'",
+        resultSetMapping = "FridayEmployeeResult")
+
+@NamedNativeQuery(name = "Schedules",
+        query = "SELECT * FROM schedule_days WHERE employeeId = 3",
+        resultSetMapping = "ScheduleResult")
+@Entity
+@Table(name = "SCHEDULE_DAYS")
+public class ScheduledDay {
+
+    @Id
+    @GeneratedValue
+    private Long id;
+    private Long employeeId;
+    private String dayOfWeek;
+
+    public ScheduledDay() {
+    }
+
+    public ScheduledDay(Long id, Long employeeId, String dayofWeek) {
+        this.id = id;
+        this.employeeId = employeeId;
+        this.dayOfWeek = dayofWeek;
+    }
+
+    public Long getEmployeeId() {
+        return employeeId;
+    }
+
+    public void setEmployeeId(Long employeeId) {
+        this.employeeId = employeeId;
+    }
+
+    public String getDayOfWeek() {
+        return dayOfWeek;
+    }
+
+    public void setDayOfWeek(String dayOfWeek) {
+        this.dayOfWeek = dayOfWeek;
+    }
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/stringcast/Message.java

@@ -0,0 +1,43 @@
+package com.baeldung.jpa.stringcast;
+
+import javax.persistence.*;
+
+@SqlResultSetMapping(name = "textQueryMapping", classes = {
+  @ConstructorResult(targetClass = Message.class, columns = {
+    @ColumnResult(name = "text")
+  })
+})
+@Entity
+public class Message {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    private String text;
+
+    public Message() {
+
+    }
+
+    public Message(String text) {
+        this.text = text;
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+}

persistence-modules/java-jpa/src/main/java/com/baeldung/jpa/stringcast/QueryExecutor.java

@@ -0,0 +1,37 @@
+package com.baeldung.jpa.stringcast;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import javax.persistence.EntityManager;
+import javax.persistence.Query;
+
+public class QueryExecutor {
+
+    public static List<String[]> executeNativeQueryNoCastCheck(String statement, EntityManager em) {
+        Query query = em.createNativeQuery(statement);
+        return query.getResultList();
+    }
+
+    public static List<String[]> executeNativeQueryWithCastCheck(String statement, EntityManager em) {
+        Query query = em.createNativeQuery(statement);
+        List results = query.getResultList();
+
+        if (results.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        if (results.get(0) instanceof String) {
+            return ((List<String>) results).stream().map(s -> new String[] { s }).collect(Collectors.toList());
+        } else {
+            return (List<String[]>) results;
+        }
+    }
+
+    public static <T> List<T> executeNativeQueryGeneric(String statement, String mapping, EntityManager em) {
+        Query query = em.createNativeQuery(statement, mapping);
+        return query.getResultList();
+    }
+
+}