Hibernate Interview Questions- Part 5

Hibernate Interview Questions- Part 5
It’s easy to feel stuck during a Hibernate interview if you don’t know how to handle tricky questions. That’s why this guide is here. It’s more than just a question list—it helps you understand the most important Hibernate topics step by step. You’ll find useful questions, clear answers, and tips that make complex ideas easy to understand.

From lazy loading to cascading, this guide gives you the confidence to explain how things work—not just memorize facts. Whether you’re reviewing or starting fresh, this page makes learning easier. Think of it as a helpful tool to boost your confidence and skills before the big day.

Answer:

Hibernate provides two fetching methods. Below are the differences between list() & iterator() method:

S.No. List() Method Iterate() Method
1 The list() method selects the required records at a time. The Iterate() method selects the required records from the table one after another.
2 It generates a single SQL select query. It generates multiple SQL select queries.
3 The List() method performs an immediate initialization of objects with the selected records or eager loading. The Iterator() method performs the lazy loading.
4 For Eg.– Selecting 4 records from a table will generate the single SQL select query. For Eg.– Selecting 4 records will generate 5 SQL select queries.

Answer:

You can configure Hibernate in three key ways:

  • By programmatically using the APIs to load the hbm file along the database driver providing connection details;
  • By specifying the details of the database connection in an XML configuration file, loaded with the hbm file. The file’s default name is hibernate.cfg.xml, but you can use another name for the file by specifying the name explicitly;
  • You can also configure Hibernate by using a .properties file with the default name of Hibernate. properties.

Answer:

Connection pooling implies that connections are reused instead of being created every time a connection is requested. To enable connection reusability, a memory cache of database connections calls a connection pool which is maintained by the connection pooling module as a layer on top of a standard JDBC driver product.

Answer:

A connection pool size has two values:

  • Minimum pool size and;
  • Maximum pool size.
max connections min connections
It is the maximum no. of connections the pool can hold. When the maximum no. of connections is exceeded, an additional request that requires the database connection will be halted till a connection from the pool becomes available & eventually times out. In case that is not possible within the time specified in the connection time-out. The maximum no. of connections limits the no. of concurrent requests that can be made against the database. It is the minimum no. of connections the pool will hold.  It is held even when there is no active request. When the minimum no. of connections is exceeded because of serving incoming requests, an additional connection is opened till the pool reaches its maximum size.

Answer:

In Hibernate, the interchange of data is preserved by using a transaction. So, when a new data exchange needs to be started, the Session.beginTransaction() function is called to start the transaction.

Answer:

Bag means a Java collection that stores elements without sequencing; however, it allows duplicate elements in the list. It is also known as the random grouping of objects in the list. A Bag collection is mapped with an element in the mapping table & initialized with java.util.ArrayList.

Answer:

Eager loading in Hibernate refers to a design pattern wherein the data initialization phase is completed on the spot. It is the best option when the relations are not too much. It helps to reduce further queries on the server.

Answer:

Lazy initialization or lazy fetching of an object means that its creation is deferred till it is used first. Lazy initialization is mainly used to avoid wasteful computation, improve performance, & reduce program memory requirements.

Answer:

  • Pessimistic locking: In pessimistic locking, the record gets locked on the update so that nobody else can access that record for updating. Thus, it becomes a read-only record until the lock is released again. Once the lock is released, the record can be locked again & gets updated for another user.
  • Optimistic locking: Optimistic locking allows multiple users to open the same record for updating. The record gets locked when updating a record only. It is the most preferred way of locking for a web application.