Java Code Geeks

Java, Rust, Scala, and Haskell all let you say “a Shape is exactly a Circle, a Square, or a Triangle, and nothing else.” They disagree sharply on what happens when you forget to handle one of them. Picture a payment result that can only ever be Approved, Declined, or Pending. Nothing else is possible, by design. Every language …

Selenium WebDriver provides several ways to interact with elements on a web page. Two commonly used methods are click() and submit(). Although both methods can be used to submit a form in certain situations, they work differently and should not be treated as interchangeable. 1. Overview Automated web testing frequently requires interacting with HTML forms. …

Java promises that Integer.MAX_VALUE + 1 always equals Integer.MIN_VALUE. That promise is exactly what let a bug hide inside the JDK’s own binary search for nine years. Try this in any Java program: take Integer.MAX_VALUE, which is 2,147,483,647, and add 1. You will not get an exception. You will not get a warning. You will get -2,147,483,648, …

List<String> and List<Integer> are the exact same class once the JVM gets involved. Here’s why Java made that trade, and what it still costs today. Ask a Java developer to run this quick check, and the answer surprises almost everyone the first time: list1.getClass() == list2.getClass() returns true, even when list1 is a List<String> and list2 is a List<Inte...

Large Language Models are fundamentally stateless. If an application sends the question “What is my favorite programming language?” to a model, the model cannot automatically know that the same user said “My favorite programming language is Java” several requests earlier. Applications therefore need a mechanism for preserving conversational context. Spring AI has traditionally p...