Proxy in Hibernate load() method (#5222)

hibernate5/src/main/java/com/baeldung/hibernate/proxy/BatchEmployee.java

@@ -0,0 +1,56 @@
+package com.baeldung.hibernate.proxy;
+
+import org.hibernate.annotations.BatchSize;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+@BatchSize(size = 5)
+public class BatchEmployee implements Serializable {
+
+    @Id
+    @GeneratedValue (strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Boss boss;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Boss getBoss() {
+        return boss;
+    }
+
+    public void setBoss(Boss boss) {
+        this.boss = boss;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/Boss.java

@@ -0,0 +1,49 @@
+package com.baeldung.hibernate.proxy;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+public class Boss implements Serializable {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Boss() { }
+
+    public Boss(String name, String surname) {
+        this.name = name;
+        this.surname = surname;
+    }
+
+    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 getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/Employee.java

@@ -0,0 +1,53 @@
+package com.baeldung.hibernate.proxy;
+
+import javax.persistence.*;
+import java.io.Serializable;
+
+@Entity
+public class Employee implements Serializable {
+
+    @Id
+    @GeneratedValue (strategy = GenerationType.SEQUENCE)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    private Boss boss;
+
+    @Column(name = "name")
+    private String name;
+
+    @Column(name = "surname")
+    private String surname;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public Boss getBoss() {
+        return boss;
+    }
+
+    public void setBoss(Boss boss) {
+        this.boss = boss;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSurname() {
+        return surname;
+    }
+
+    public void setSurname(String surname) {
+        this.surname = surname;
+    }
+}

hibernate5/src/main/java/com/baeldung/hibernate/proxy/HibernateUtil.java

@@ -0,0 +1,57 @@
+package com.baeldung.hibernate.proxy;
+
+import org.apache.commons.lang3.StringUtils;
+import org.hibernate.SessionFactory;
+import org.hibernate.boot.Metadata;
+import org.hibernate.boot.MetadataSources;
+import org.hibernate.boot.SessionFactoryBuilder;
+import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
+import org.hibernate.service.ServiceRegistry;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.net.URL;
+import java.util.Properties;
+
+public class HibernateUtil {
+
+    private static SessionFactory sessionFactory;
+    private static String PROPERTY_FILE_NAME;
+
+    public static SessionFactory getSessionFactory(String propertyFileName) throws IOException {
+        PROPERTY_FILE_NAME = propertyFileName;
+        if (sessionFactory == null) {
+            ServiceRegistry serviceRegistry = configureServiceRegistry();
+            sessionFactory = getSessionFactoryBuilder(serviceRegistry).build();
+        }
+        return sessionFactory;
+    }
+
+    private static SessionFactoryBuilder getSessionFactoryBuilder(ServiceRegistry serviceRegistry) {
+        MetadataSources metadataSources = new MetadataSources(serviceRegistry);
+        metadataSources.addPackage("com.baeldung.hibernate.proxy");
+        metadataSources.addAnnotatedClass(Boss.class);
+        metadataSources.addAnnotatedClass(Employee.class);
+
+        Metadata metadata = metadataSources.buildMetadata();
+        return metadata.getSessionFactoryBuilder();
+
+    }
+
+    private static ServiceRegistry configureServiceRegistry() throws IOException {
+        Properties properties = getProperties();
+        return new StandardServiceRegistryBuilder().applySettings(properties)
+            .build();
+    }
+
+    private static Properties getProperties() throws IOException {
+        Properties properties = new Properties();
+        URL propertiesURL = Thread.currentThread()
+            .getContextClassLoader()
+            .getResource(StringUtils.defaultString(PROPERTY_FILE_NAME, "hibernate.properties"));
+        try (FileInputStream inputStream = new FileInputStream(propertiesURL.getFile())) {
+            properties.load(inputStream);
+        }
+        return properties;
+    }
+}