Top 50 Hibernate Interview Questions & Answers . HQL is very efficient, simple and flexible query language to do various .. Download PDF. during your interview, normally questions start with some basic concept of the subject Hibernate is an Object-Relational MappingORM solution for JAVA and it. Hibernate is an ORM (object-relational mapping) tool for Java programming language. Download Hibernate Interview Questions PDF.
|Language:||English, German, Japanese|
|ePub File Size:||30.47 MB|
|PDF File Size:||15.57 MB|
|Distribution:||Free* [*Sign up for free]|
learn more about Hibernate? Then check out our detailed Hibernate Interview Questions! You can also download our FREE Hibernate Tutorial!. Interview Questions And Answers, Job Interviews are always stressful even for job seekers who have PDF was generated at Saturday 10th January, Hibernate interview questions and answers for experienced and beginners too, spring hibernate questions with detailed answers. Free Java Interview Questions eBook (+ Questions). We promise not to spam you. You can unsubscribe at.
Overall hibernate is the best choice in current market for ORM tool, it contains all the features that you will ever need in an ORM tool. Hibernate supports inheritance, associations and collections.
Hibernate built-in transaction management removes the usage of try-catch blocks. For JDBC, we need to write native sql queries. Hibernate supports caching that is better for performance, JDBC queries are not cached hence performance is low.
Hibernate provide option through which we can create database tables too, for JDBC tables must exist in the database.
Hibernate supports JPA annotations, so code is independent of implementation and easily replaceable with other ORM tools. JDBC code is very tightly coupled with the application. Name some important interfaces of Hibernate framework?
Some of the important interfaces of Hibernate framework are: SessionFactory org. SessionFactory : SessionFactory is an immutable thread-safe cache of compiled mappings for a single database. We need to initialize SessionFactory once and then we can cache and reuse it. SessionFactory instance is used to get the Session objects for database operations. Session org. Session : Session is a single-threaded, short-lived object representing a conversation between the application and the persistent store.
It wraps JDBC java. Connection and works as a factory for org. Session object is the interface between java application code and hibernate framework and provide methods for CRUD operations.
Transaction org. Transaction : Transaction is a single-threaded, short-lived object used by the application to specify atomic units of work.
Hibernate Interview Questions & Answers
A org. Session might span multiple org. Transaction in some cases. What is hibernate configuration file? Hibernate configuration file contains database specific configurations and used to initialize SessionFactory. We provide database credentials or JNDI resource information in the hibernate configuration xml file. Some other important parts of hibernate configuration file is Dialect information, so that hibernate knows the database type and mapping file or class details.
What is hibernate mapping file? Hibernate mapping file is used to define the entity bean fields and database table column mappings. Name some important annotations used for Hibernate mapping?
Hibernate Interview Questions and Answers
Hibernate supports JPA annotations and it has some other annotations in org. Some of the important JPA and hibernate annotations used are: javax.
Entity: Used with model classes to specify that they are entity beans.
Table: Used with entity beans to define the corresponding table name in database. Access: Used to define the access type, either field or property.
Id: Used to define the primary key in the entity bean. EmbeddedId: Used to define composite primary key in the entity bean. Column: Used to define the column name in database table. GeneratedValue: Used to define the strategy to be used for generation of primary key. Used in conjunction with javax. GenerationType enum. OneToOne: Used to define the one-to-one mapping between two entity beans. Cascade: Used to define the cascading between two entity beans, used with mappings.
It works in conjunction with org. CascadeType javax. PrimaryKeyJoinColumn: Used to define the property for foreign key. Used with org. GenericGenerator and org. We need to add following in hibernate configuration file to enable viewing SQL on the console for debugging purposes: Following are the two types of collections in hibernate: Sorted Collection b.
Order Collection. Hibernate can be used seamlessly with any type of database as its database independent while in case of JDBC, developer has to write database specific queries. In case of hibernate, there is no need to create connection pools as hibernate does all connection handling automatically while in case of JDBC, connection pools need to be created. We can get hibernate statistics using getStatistics method of SessionFactory class as shown below: Hibernate provides dirty checking feature which can be used to reduce database write times.
Dirty checking feature of hibernate updates only those fields which require a change while keeps others unchanged. Callback interfaces of hibernate are useful in receiving event notifications from objects. For example, when an object is loaded or deleted, an event is generated and notification is sent using callback interfaces. When an instance was earlier associated with some persistent context e.
Following are the four ORM levels in hibernate: Pure Relational b. Light Object Mapping c. Medium Object Mapping d. Full Object Mapping. How It Works?
Hibernate Related Tutorials
Transaction management is the process of managing a set of statements or commands. In hibernate; transaction management is done by transaction interface as shown in below code: We can use any of the following two methods of hibernate configuration: XML based configuration using hibernate.
Programmatic configuration Using code logic.
In hibernate; we have following two types of mapping associations between entities: One-to-One Association b. Many-to-Many Association. Hibernate provides following four ways to fetch objects from database: Using HQL b.
Using identifier c. Using Criteria API d. Using Standard SQL. Database primary key is specified in the configuration file hbm. Generator can also be used to specify how primary key is being created in the database.
In the below example, deptId acts as primary key: Objects which have been detached and are no longer associated with any persistent entities can be reattached by calling session. Hibernate second level cache can be disabled using any of the following ways: Using cache provider as org. What Is Orm Metadata?
With hibernate 3.
Hibernate Interview Questions
JMX provides tools for development of efficient and robust distributed, web based solutions. Hibernate session factory can be bound to JNDI by making configuration changes in hibernate. Managed associations relate to container management persistence and are bi-directional while hibernate associations are unidirectional. What Is Light Object Mapping? Light Object Mapping is one of the levels of ORM quality in which all entities are represented as classes and they are mapped manually.
Load configuration file and create object of configuration class.
Using configuration object, create sessionFactory object. From sessionFactory, get one session.
Create HQL query. Execute HQL query and get the results.
Results will be in the form of a list. Session Factory level interceptor and session level interceptor. These Interceptors can be used to have code for certain type of logic to be called for every lifecycle method of session.
Hibernate interview question How can multiple threads access session factory simulteneously to create session instance? Hibernate interview answer session factory is thread-safe, so it is okay to be used by many threads to have session from session factory, but I think session is not thread safe and it should be used by one thread at a time, and after use, session has to be flushed and closed.
Hibernate interview question How many ways Hibernate manages concurrency? Hibernate interview answer Hibernate has different ways of managing concurrency. These are automatic versioning, detached object and extended user sessions. What is the difference between uni-directional and bi-directional associations?
Bi-directional association allows object querying from both directions of fetching object instances. What are the different contextual session in Hibernate?
Hibernate interview answer There are three different types of contextual session Hibernate provides, these are JTA session context, local thread session context.
JTA session context is applicable in case Hibernate session is running in JTA Java Transaction API , request thread in case of local thread session, and managed session, requires application to open, close and flush session, so creation of session should be handled by application only.
Hibernate interview answer HQL is fully object oriented, with support for object inheritence, polymorphism and association, but SQL is more of Relational with structured form of queries.
Hibernate interview Question What are the different scopes one can introduce while using Interceptors with Hibernate? Probably, one can use interceptors with hibernate Session scoped or SessionFactory scoped contexts, while using Interceptors with Hibernate.
Hibernate Interview Questions.pdf
How many ways client application that uses Hibernate to react to certain events? These are either Interceptors or event systems.
What is the difference between hibernate and spring JDBC template? List any advantages and disadvantages What is the difference between hibernate and spring JDBC template? Latest Answer: The main diffrence between Entity Bean and hibernate is Entity Bean is a heavy weight component and hibernate is a light weight component. Latest Answer: HQL provides four ways of expressing inner and outer joins:1 An ordinary join in the from clause2 A fetch join in the from clause3 A theta-style join in the where clause4 An implicit association joinThere are three states that exist for any instance of a class.
Java bean is a simple resuble component.
What is the difference between the session. Those instances that were used in Session methods like save, saveOrUpdate or update to be inserted or updated in database table, and then session is flushed and closed, now these objects are in JVM, but these are not bound to any session.
When an instance was earlier associated with some persistent context e. Deepak Upadhyay.