Introduction In this post, we will cover advanced stream pipeline concepts in Java 8. We will analyze chaining Optionals, predefined collectors, and learn how to use groupingBy, partitioningBy, and mapping methods. You can find the source code on GitHub. Chaining Optionals Chaining optionals help eliminate the nested if-statements for Optional variables. The function…

Giris Bu yazida son yillarda yurtdisinda girdigim yazilim mulakatlarin bir ozetini yapacagim. Bunlarin buyuk bir kismi gunluk hayatta karsilasmadigimiz tipte olan ama hayatimizin da bir gercegi olan kodlama problemleridir. Ayni hatalari sizin de yapmamaniz icin ogrendigim dersleri de paylasacagim. Siz de deneyimlerinizi yorumlara yazabilir, is arayan tanidiklarinizla yaziyi paylasabilirsiniz. Bazen yurtdisi…

Introduction In this post, we will cover how to create a Java Priority Queue with a Comparator. We are going to practice the problem defined at HackerRank. Let’s look at the problem description. Problem Definition Several students in a school are waiting to be served. …

Introduction In this post, we will cover creating primitive streams, using Optional types with primitives, and summarizing statistics in a single pass. Primitive Streams There are three types of primitive streams: IntStream (int, short, byte, and char), LongStream (long), and DoubleStream (double and float). Creating Primitive Streams Creating primitive streams is the same as a regular…

Introduction In this post, we will follow the test pyramid approach in order to develop a simple Spring Boot application, which has the following classes: Controller, Service, Repository, and Domain. We will focus on Unit and Integration Tests for the Controller, Service, Repository classes.

Introduction In this post, we will cover the streams in Java 8. We will discover the three parts of the pipeline: source, terminal, and intermediate operations. What is a stream pipeline? Stream operations are divided into intermediate and terminal operations and are combined to form stream pipelines. …

Introduction Functional interfaces are the basics of functional programming in Java 8. If you master the six basic interfaces, you can derive the rest and understand the streams. In this section, we will cover the common functional interfaces in java.util.function package: Supplier, Consumer, Predicate, Function, UnaryOperator, and BinaryOperator. Class Hierarchy The diagram shows…

Introduction The collection interfaces are divided into two groups: the most basic interface java.util.Collection, and other collection interfaces based on java.util.Map. In this section, we will cover four main interfaces in the Java Collections Framework: List, Set, Map, and Queue. List You usually use a list when you want an ordered collection…

Introduction Generics enable types (classes and interfaces) to be parameters when defining classes, interfaces, and methods. It enables you to re-use the same code. In this section, we will cover Generic Classes, Generic Interfaces, Generic Methods, and Bounded Type Parameters. Type Parameter Naming Conventions By convention, type parameter names are single, uppercase letters. …