JavaWorld Core Java

• Java Challengers #4: Comparing Java objects with equals() and hashcode() September 20, 2018
  In this Java Challenger you’ll learn how equals() and hashcode() combine to make object comparisons efficient and easy in your Java programs. Simply put, these methods work together to verify if two objects have the same values.  Without equals() and hashcode() we would have to create very large "if" comparisons, comparing every field from an […]
• What is the JRE? Introduction to the Java Runtime Environment September 11, 2018
  Together, the Java Development Kit (JDK), the Java Virtual Machine (JVM), and the Java Runtime Environment (JRE) form a powerful trifecta of Java platform components for developing and running Java applications. I've previously introduced the JDK and JVM. In this quick tutorial, you'll learn about the JRE, which is the runtime environment for Java.Practically speaking, a […]
• JDK 12 roadmap: Java 12 gets first targeted feature August 28, 2018
  While Java Development Kit (JDK) 11 won’t arrive for another month, work proceeds on its successor, JDK 12, with a switch expressions capability lined up for the release, expected in March 2019. Simplified coding is a goal of this capability.Switch expressions, which will be in beta state in JDK 12, extends the switch statement so […]
• Java 101: Mastering Java exceptions, Part 2 August 21, 2018
  JDK 1.0 introduced a framework of language features and library types for dealing with exceptions, which are divergences from expected program behavior. The first half of this article covered Java's basic exception handling capabilities. This second half introduces more advanced capabilities provided by JDK 1.0 and its successors: JDK 1.4, JDK 7, and JDK 9. Learn […]
• What is the JDK? Introduction to the Java Development Kit August 9, 2018
  The Java Development Kit (JDK) is one of three core technology packages used in Java programming, along with the JVM (Java Virtual Machine) and the JRE (Java Runtime Environment). It's important to differentiate between these three technologies, as well as understanding how they're connected: The JVM is the Java platform component that executes programs. The […]
• Java Challengers #3: Polymorphism and inheritance July 19, 2018
  According to the legend Venkat Subramaniam, polymorphism is the most important concept in object-oriented programming. Polymorphism--or the ability of an object to execute specialized actions based on its type--is what makes Java code flexible. Design patterns like Command, Observer, Decorator, Strategy, and many others created by the Gang Of Four, all use some form of […]
• Java 101: Mastering Java exceptions, Part 1 June 26, 2018
  Java exceptions are library types and language features used to represent and deal with program failure. In the first half of this article you'll learn about basic language features and library types that have been around since Java 1.0. In the second half you'll discover advanced capabilities introduced in more recent Java versions. If you've […]
• Java 101: Datastructures and algorithms in Java, Part 5 June 8, 2018
  In Part 4, I introduced all the things you can do with singly linked lists and their algorithms in Java. While singly linked lists have many uses, they also present some restrictions. For one thing, singly linked lists restrict node traversal to a single direction: you can't traverse a singly linked list backward unless you […]
• Java Challengers #2: String comparisons May 30, 2018
  In Java, the String class encapsulates an array of char. Put simply, String is an array of characters used to compose words, sentences, or any other data you want.Encapsulation is one of the most powerful concepts in object-oriented programming. Because of encapsulation, you don’t need to know how the String class works; you just need […]
• Oracle plans to dump risky Java serialization May 24, 2018
  Oracle plans to drop from Java its serialization feature that has been a thorn in the side when it comes to security. Also known as Java object serialization, the feature is used for encoding objects into streams of bytes. Used for lightweight persistence and communication via sockets or Java RMI, serialization also supports the reconstruction of […]