Roy Tutorials

Introduction In this tutorial I will show you how to read CSV file using Java 7 or later versions. I will use here Java’s new feature Path API. I will also use Java 8’s Stream API to split the comma separated line and map the record into String array. I am going to show you how to read file content…

What is busy waiting or spinning? Busy spinning or waiting in multi-threading environment is a technique in which a process repeatedly checks if a particular condition is true instead of wait() or sleep() method and without releasing the CPU. In other words busy spinning is one of the techniques to wait for events without releasing CPU. Busy waiting or spinning…

Spring framework provides bean life cycle call back methods to perform some additional tasks which you may want to perform when a bean is initiated or created or when a bean is about to get destroyed. Therefore you can run a method which will do some initialization process during bean initialization and you can run another method which will do…

Spring InitializingBean and DisposableBean are the interfaces used in life cycle of Spring beans management. Each of these interfaces has only one method. InitializingBean has a method called afterPropertiesSet() and DisposableBean has a method called destroy(). Spring container runs the method afterPropertiesSet() once the bean properties have been set and Spring container runs destroy() method once Spring container releases the…

Introduction In this tutorial we will discuss on Spring custom init() and destroy() methods. These methods are call back methods which used in Spring life cycle. You can use these methods to to some initialization and clean up jobs just after the bean is created by the Spring container or just before the bean is about to be destroyed by…

BeanPostProcessor in Spring is used for extending the functionality of framework if want to do any configuration Pre- and Post- bean initialization done by spring container. By default, Spring will not aware of the @PostConstruct and @PreDestroy annotation. To enable it, you have to either register CommonAnnotationBeanPostProcessor or specify <context:annotation-config/> in the bean configuration file. Here CommonAnnotationBeanPostProcessor is predefined BeanPostProcessor…

We will discuss about how to exchange data between two threads or a pair of threads. The Exchanger class under java.util.concurrent package was introduced in JDK 1.5 along with CyclicBarrier, CountDownLatch to exchange data between two threads only. A synchronization point at which two threads can pair and exchange data within pair using the exchange() method of the Exchanger class….

Introduction Here I am going to tell you how fork join works in Java and how to use fork join in Java. Fork join was introduced in java version 1.7. JDK 7 and Java version 7 introduced many good features, such as, string in switch case, multi-catch block, automatic resource management, etc. and fork join was one of them. Fork…

Here I am going to discuss about whether it is a good idea to send parameter in request body of the HTTP GET request or not. Request body is also known as payload of the request. I will also discuss about idempotent and safe http methods. Generally payload in the body is sent for POST, PUT, etc. http methods where…

Hibernate Object States In this tutorial I will discuss what are the states of objects (transient persistent detached objects) in Hibernate framework. You might be knowing that Hibernate is an ORM (Object Relational Mapping), which is an automated persistent of objects in a Java application to the tables in a relational database. Hibernate defines and supports three different object states:…