Core Java

In an interview, one of my friends was asked that if we have two Integer objects, Integer a = 127; Integer b = 127; Why a == b evaluate to true when both are holding two separate objects? In this article, I will try to answer this question and also try to explain the answer. Short Answer The short answer to this question is, ...

Previously we had a look at the iterator pattern. The mediator pattern is way different on what it tries to achieve. It is one of the behavioural patterns and its purpose is to alter the way objects communicate with each other. Instead of the objects communicating with each other directly the mediator will handle the objects interaction. For example imagine ...

When you design a method in a Java class, some parameters may be optional for its execution. No matter it is inside a DTO, a fat model domain object, or a simple stateless service class, optional method parameters are common. From this article you will learn how to handle optional parameters in Java. We’ll focus on regular method, class constructors ...

Scripting is one of the most popular ways to make your application adjustable for client needs right at runtime. As always, this approach brings not only good, e.g. there is a well-known trade-off between flexibility and manageability. This article is not one of those which theoretically discuss pros and cons, it practically shows different ways of how to adopt scripting ...

JDK 12 introduces a new method to the Files class. The method, Files.mismatch(Path,Path), has been introduced to JDK 12 via JDK-8202302 and is available in JDK 12 Early Access Build 20 (same early access build that supports the new {@systemProperty} Javadoc tag). JDK-8202302 [“(fs) New Files.mismatch method for comparing files”] adds the Files.mismatch(Path,Path) method “to compare the contents of two ...

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JDK 12 Early Access Build 20 (2018/11/15) is available and can be used to try out the new Javadoc tag {@systemProperty}. The new {@systemProperty} Javadoc tag is discussed in the core-libs-dev mailing list message “FYI: new javadoc tag to document system properties” and was introduced in response to JDK-5076751 [“System properties documentation needed in javadocs”]. The {@systemPropery} Javadoc tag displays ...

When we create a variable in both parent and child class with the same name, and try to access it using parent’s class reference which is holding a child class’s object then what do we get? In order to understand this, let us consider below example where we declare a variable x with the same name in bothParent andChild classes. class ...

This is part 5 of the series called “Functional Java by Example”. In previous part we stopped mutating our documents and returned copies of the data. Now, we need to move some I/O away. If you came for the first time, it’s best to start reading from the beginning. It helps to understand where we started and how we moved ...