How to use Flink Java DataStream API for local testing

Just explored the power of Java Stream API — a game changer for working with collections. With streams, you can filter, transform, and aggregate data in a clean and readable way.

Just published today: a practical guide to Java Streams—creating from collections, lazy vs. terminal ops, map vs. flatMap, collectors (toList, groupingBy, joining), optional chaining, and when not to use streams. https://lnkd.in/d9gdZFht

Java 25 keeps improving the Stream API: meet Stream Gatherers. They let you define custom operations like chunking, windowing, or filtering by unique keys, all without external libraries. Here’s a quick example that keeps only one user per country using a custom Gatherer: clean, flexible, and fully integrated into the Stream API.

🧩 Day 20: Java Collections – Map Interface 🔹 Topics Covered: 1. Introduction to Map Interface Unlike List and Set, a Map stores data as key–value pairs. Each key is unique, but values can be duplicated. Common methods: put(), get(), remove(), containsKey(), containsValue(), keySet(), values(), entrySet()

Here's a quick video about resolving parts of a station to add components to through java. Once you understand the hierarchy, you can make this work with any network and levels you'd want to go.

Introduction of JDK, JRE, JVM: JDK – Java Development Kit Full package for developers Contains JRE + development tools Tools include: javac (compiler), java, jar, javadoc, etc. Used to write, compile, and run Java programs JRE – Java Runtime Environment Environment to run Java applications Contains JVM + runtime libraries + package classes Does not include development tools (like compiler) Used only for execution, not for development JVM – Java Virtual Machine Execution engine that runs Java bytecode Converts bytecode to machine code (platform independent → platform dependent) Handles memory management, class loading, garbage collection

🚀 Let’s dive deeper into Java Sealed Classes: The permits keyword! Yesterday we talked about what sealed classes are and why they’re useful. Today, we’ll explore how to control inheritance using permits. What is permits? The permits keyword specifies exactly which classes are allowed to extend a sealed class. This ensures the hierarchy is strictly controlled and prevents unexpected or unwanted subclassing. Important Rule: Any class listed in the permits clause must be declared as one of the following: - final → cannot be subclassed further - sealed → can have its own limited set of subclasses - non-sealed → removes the restriction, allowing open inheritance ✅ Key takeaway: The permits keyword combined with final, sealed, or non-sealed lets you design safe, predictable, and maintainable class hierarchies. #Java #Java17 #SealedClasses #PermitsKeyword #OOP #CleanCode #ProgrammingTips #SoftwareDevelopment

Day 3 — Exception Handling in Java Continuing the 100 Days of Java + Spring Boot challenge with Faisal Memon. Covered key concepts: try-catch-finally, throw & throws, checked vs unchecked exceptions, and try-with-resources. Resources: https://lnkd.in/gtGcjg2i Consistency is the goal. #Java #SpringBoot #100DaysOfCode #LearningJourney

🔒 Understanding the final keyword in Java The final keyword adds safety and stability to your code by preventing unwanted changes. It can be used in three main ways: 🧩 With Variables – once assigned, the value can’t be changed. 🧩 With Methods – prevents overriding in subclasses. 🧩 With Classes – stops inheritance altogether. Simple yet powerful — final protects what’s meant to stay constant. #Java #OOPs #finalKeyword #JavaConcepts #CodingBasics #LearnJava