Red Hat Certificate Of Expertise In Persistence Exam Ies (Ex297K)

• Experienced Java application developers and architects
• Business component and database developers Prerequisites
• Red Hat recommends that candidates for this exam earn Red Hat Certified
• JBoss Developer (RHCJD) before attempting this exam, but it is not required
• Have taken the JBoss Hibernate Technology (JB297) course or have extensive work experience with JPA and Hibernate
• Have familiarity working in a Red Hat Enterprise Linux environment
• Review the Red Hat Certificate of Expertise in Persistence exam (EX297) objectives

1. Configure JPA/Hibernate 

• Configure PersistenceUnit properties, including: 

◦ Location of configuration files 

◦ Java EE-specific configuration details ◦ Java SE-specific configuration details 

◦ Hibernate-specific configuration details 

• Connect to a PersistenceUnit from a Java SE application 
• Connect to a PersistenceUnit from a Java EE application 
• Override PersistenceUnit default property values 

1. Map a single table or object 

• Understand the behavior of the id generators, including how and when the value is generated 
• Understand how to map a primary key, including: 

◦ Using generated keys 

◦ Mapping simple business keys 

◦ Mapping compound keys 

• Understand object identity and business equivalence 
• Configure database-specific information, such as table name, column name, column width, and 
• column attributes (nullable, unique, type, and so on) 
• Convert an existing Java object into a persistent object using JPA/Hibernate 

• Map basic JPA data types to corresponding database types 
• Given an existing database table, create a new persistent Java object to map that table 
• Understand how and when to use lazy versus eager loading 
• Understand and use optimal mapping strategies for collections and value types 
• Handle Java/object model-specific properties and behaviors in a persistent object. This includes: 

◦ Serialization 

◦ Transient properties 

◦ Generated and calculated properties 

◦ Immutable properties 

◦ Value types 

◦ Co-dependent properties (i.e. where a property's valid values depend on the value of another property) 

1. Map object relationships with JPA/Hibernate 

• Understand how to map relationships, including but not limited to: 

◦ Value relationships (for example, has-a details object) 

◦ Parent/child relationships 

◦ One-to-one relationships (both unidirectional and bidirectional) 

◦ Many-to-one and one-to-many relationships (both unidirectional and bidirectional) 

◦ Many-to-many relationships (both unidirectional and bidirectional) 

• Understand default mapping behaviors, including but not limited to: 

◦ Foreign key names 

◦ Association table names 

• Understand the use of foreign keys and join tables when creating relationships 
• Understand how to map a compound primary key based on the relationship 
• Understand JPA/Hibernate collections (sets, maps lists, and bags) and how they map to object and table relationships 
• Understand the performance impacts of the different collections 

• Understand how and when to use lazy versus eager loading, including the performance and code impacts of both 
• Given a set of existing tables and relationships, create a persistent Java object graph matching 
• the database 
• Map an existing object model, including various associations, to a persistence store 
• Determine optimal loading strategies for a given business process 

1. Map hierarchical object relationships with JPA/Hibernate 

• Understand how to represent different object hierarchies using JPA/Hibernate 
• Convert an existing Java object hierarchy to persistent objects using JPA/Hibernate 
• Represent an existing set of table relationships as an object hierarchy (for example, savings account, credit card, and loan account) 
• Understand polymorphic queries and associations 

• Understand the benefits and limitations of the different inheritance strategies 
• Analyze and determine optimal database representations for different object hierarchies 

1. Understand transactional behavior (ACID) 

• Acquire and use a transaction context under: 

◦ Java EE/CMT ◦ Java EE/BMT 

◦ Java SE using JPA APIs 

• Understand how the persistence context is bound to the transaction in Java EE 
• Understand transactional context propagation with EJB3 
• Understand the consequences of a transaction rollback at the persistence context level 
• Understand transactional concurrency risks 

• Evaluate data loss/corruption versus performance trade-offs 

1. Retrieve persistent objects 

• Understand JPA/Hibernate loading strategies: 

◦ Lazy loading 

◦ Subselect loading 

◦ Batch loading 

• Understand and use advanced query options: 

◦ HQL/JPA QL 

◦ Criteria APIs 

◦ Native queries (SQL) 

• Use the runtime eager fetching feature 
• Use named parameters 
• Anticipate and avoid LazyInitializationException 
• Analyze and improve JPA/Hibernate performance 
• Understand and use JPA optimistic locking and Hibernate pessimistic locking extended features 

1. Manipulating persistent objects 

• Understand entity states, such as: 

◦ transient 

◦ persistent 

◦ attached 

◦ detached 

◦ removed 

• Understand how to change the state of an entity/entity graph using JPA APIs 
• Understand the lifecycle of the persistence context and its impact on the entities being managed 
• Apply JPA/Hibernate batching features: 

◦ API usage patterns 

◦ DML queries 

• Determine and apply optimal implementation and cascade settings to manipulate an object graph 
• Evaluate when to use batching