Book Image

Kotlin for Enterprise Applications using Java EE

By : Raghavendra Rao K
Book Image

Kotlin for Enterprise Applications using Java EE

By: Raghavendra Rao K

Overview of this book

Kotlin was developed with a view to solving programmers’ difficulties and operational challenges. This book guides you in making Kotlin and Java EE work in unison to build enterprise-grade applications. Together, they can be used to create services of any size with just a few lines of code and let you focus on the business logic. Kotlin for Enterprise Applications using Java EE begins with a brief tour of Kotlin and helps you understand what makes it a popular and reasonable choice of programming language for application development, followed by its incorporation in the Java EE platform. We will then learn how to build applications using the Java Persistence API (JPA) and Enterprise JavaBeans (EJB), as well as develop RESTful web services and MicroServices. As we work our way through the chapters, we’ll use various performance improvement and monitoring tools for your application and see how they optimize real-world applications. At each step along the way, we will see how easy it is to develop enterprise applications in Kotlin. By the end of this book, we will have learned design patterns and how to implement them using Kotlin.
Table of Contents (13 chapters)

Exception handling

Exception handling is crucial for enterprise applications. Exceptions can arise in the middle of execution, such as a PersonCreationException in our example. Once an exception arises somewhere within the execution, the data will either be persisted in the database or the complete transaction will be rolled back, depending on the exception.

For example, let's say our createPerson() function throws PersonCreationException:

public class PersonCreationException extends Exception {
public PersonCreationException(String message) {
super(message)
}
}

Since PersonCreationException is a checked exception, the transaction will not be rolled back if the exception is thrown during the execution of the createPerson() function. These kinds of exceptions are commonly called application exceptions.

Application exceptions are checked exceptions that either have to be handled...