Java Training : Introduction to the Java Persistence API Version 2 (JPA 2)

Introduction to the Java Persistence API Version 2 (JPA 2)

Java Training Overview

As part of the complete overhaul of the Enterprise JavaBeans (EJB) specification, database persistence was broken out into a completely separate specification, the Java Persistence API (JPA). JPA replaces entity beans with powerful new Object-Relational Mapping (ORM) capabilities based on proven technologies such as Toplink and Hibernate. This course includes all important features from JPA 2, and is also suitable for users of the 1.0 release.

JPA supports a POJO (Plain Old Java Object) based model using annotations which lets you develop persistent classes following common Java idioms. It supports entity relationships, inheritance, polymorphism, composition, and much more. The Java Persistence Query Language (JPQL), which is based on SQL but operates on the object model, provides a powerful bridge between the object and relational worlds. JPA also allows you to express queries using native SQL, including the capability to map the SQL query results to persistent entities

This course covers everything you need to know to begin working with the Java Persistence API in a very short time. It covers all the important concepts necessary to access and update data stored in relational databases. It includes an extensive series of labs to exercise all major capabilities.

Java Training Skills Gained

Understand the JPA architecture

Create JPA based applications

Understand and use JPA to map persistent objects to the database

Create JPA persistence units, and understand JPA persistence contexts and the Entity Lifecycle

Use the JPA EntityManager

Work with queries and JPQL (Java Persistence Query Language), as well as the Criteria API (JPA 2)

Understand and work with collections & associations

Value and Entity Types
Bidrectional and unidirectional
1-1, 1-N, N-N

Use versioning support for optimistic locking

Map inheritance hierarchies using JPA

Performance tune your JPA applications

Understand JPA transaction support

Understand the relationship between JPA / EJB3

Use JPA entities from session beans (Optional)

Be familiar with Spring support for JPA (Optional)

Hands-On

many hands-on labs (minimum 50% of course)

Prerequisites

Working knowledge of Java programming, including use of inheritance, interfaces, and exceptions

Supported Platforms

Standard: Java 8 and Eclipse IDE
Standard Web Container: Tomcat
Other Available IDEs IntelliJ IDEA, IBM RAD (upon request)

Java Training Course Duration

3 Days

Java Training Course outline

Session 1: Introduction to Java Persistence API (JPA)

Overview

Persistence Layers, Object-Relational Mapping (ORM), JDBC
JPA Overview

Mapping with JPA

Entities and @Entity, ids and @Id,
Generated Id Values
Basic Mapping Types

Persistence Unit and EntityManager

Persisting to the DB, the EntityManager API
Persistence Units, Config, Persistence Context
Retrieving Persistent Entities with find()

More About Mappings

Default Mappings, @Basic, @Column
Field vs. Property Access
Temporal (Date/Time) Mappings

Logging Options (Provider based)

Session 2: Updates and Queries

Inserting and Updating - Persisting new Entities, Updating an Instance, Removing an Instance
Querying and JPQL
- Entity Based Queries, SELECT ,WHERE
- Query Interface, Executing Queries, Generic Queries (JPA 2)
- JPQL Operators, Expressions, and Parameters
- Named Queries
Additional Query Capabilities
- Projection query, Ordering, Aggregate Query, Build Update and Delete
Embedded Objects
- @Embeddable, @Embedded
- Defining and using Embedded Objects
Compound Primary Keys - @EmbeddedID, @IDClass, Defining Compound Keys

Session 3: The Persistence Lifecycle

Transaction Overview and Transactions in JPA
- Transaction Overview
- EntityTransaction API (including JTA and resource-local EntityManager)
The Persistence Lifecycle
- JPA Entity States (New, Managed, Detached, Removed), and Entity State Diagram
- Persistence Context - Lifespan, Propagation
- Synchronization to the DB
Versioning and Optimistic Locking
- Overview, Detached Instances
- Versioning, @Version, Optimistic Locking
Lifecycle Callbacks
- @PrePersist, @PostPersist, etc.
- Entity Listeners, @EntityListeners

Session 4: Entity Relationships

Relationships Overview: Object Relationships, Participants, Roles, Directionality, Cardinality
Relationship Mapping
- Mapping Overview (1-1, 1-N, N-1, N-N)
- Unidirectional and Bidirectional
- @ManyToOne, @OneToMany, Table Structures
- Relationship Inverse - Owning Side
- Collection Types (List, Set, etc)
- Cascading Over Relationships (including orphanRemoval - JPA 2)
- @ManyToMany, @OneToOne
- Lazy and Eager Loading
- Queries Across Relationships (Inner Joins, Outer Joins, Fetch Joins)
Entity Inheritance Mapping
- Overview
- Single Table Mapping
- Joined (Table per Subclass) Mapping
- Table per Concrete Class Mapping
- Pros and Cons
Element Collections (JPA 2)
- Overview, Collections of Value Objects, @ElementCollection, @CollectionTable
- Using Element Collections
- Collections of Embeddables

Session 5: The Crietria API (JPA 2)

Overview of the Criteria API
Path Expressions, Building Queries (CriteriaBuilder, CriteriaQuery, Subquery, Predicate, Expression, Order, Selection, Join)
Executing Queries and Accessing Results

Session 6: Additional JPA Capabilities

XML Mapping Files
Bean Validation (JPA 2)
Best Practices
- Primary Keys, Named Queries, Lazy/Eager Loading, Transactional Semantics, Encapsulation, Report Queries

Session 7: Integration

Data Access Objects (DAO) and Java SE Integration (Optional)
- DAO Overview
- JpaUtil Class for EntityManager management in Java SE
- Lifecycle Considerations
Integration with EJB (Optional)
- Using JPA with Session Beans
- Container Managed (Injected) Entity Manger
- JTA Transactions and Lifecycle Considerations
- Extended Persistence Contexts
Using JPA with Java Web Apps
- Using EntityManager in Web apps - request scoping
- Lazy Loading - Open EntityManager in View Pattern
Integration with Spring (Optional)
- Injection of EntityManger, EntityManagerFactory
- LocalEntityManagerFactoryBean
- JPA/Spring Based DAO