📘 Day 62 – Core Java (Thread Creation & Life Cycle) ✅ ✔️ Learned the Thread life cycle and how threads work from creation to termination. ✔️ Learned two ways to create a thread in Java: 1️⃣ By extending the Thread class – override run() and call start() using the object. 2️⃣ By implementing the Runnable interface – implement run(), create a Thread object, and call start(). ✔️ Understood how start() begins a new thread while run() defines the task inside the thread.
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How Java Virtual Threads Handle I/O Blocking When a virtual thread in Java performs a blocking I/O call — for example, SocketChannel.read() — it doesn’t actually block a real OS thread. Instead, under the hood: 1️⃣ The JVM detects the blocking call. 2️⃣ The virtual thread unmounts from its carrier (real) thread. 3️⃣ Its Java stack is saved in a heap continuation. 4️⃣ The carrier thread is freed to run other tasks. 5️⃣ When the I/O operation completes, the virtual thread is resumed from the exact point it paused. This means that the JDK internals were significantly reworked to support this model. If you want to understand the mechanism deeper, check out the implementation of SocketChannelImpl.
A quick java tip about primitives In Java, the GC does not clean up primitives. Primitives aren’t stored on the heap; they live on the stack or inline inside objects, so they don’t need garbage collection. GC only collects heap objects like Integer, arrays, and anything created with new. Primitive fields inside an object are just part of that object’s memory and disappear when the object itself is collected. #java #javadeveloper #javaprogramming #programming
Collection vs Collections in Java — Know the Difference! Collection (Interface) :- It is an interface which should be used when we want to represent a group of individual object then we need to go for collection. 1. Belongs to java.util package 2. It’s the root interface of the Java Collections Framework 3.Implemented by interfaces like List, Set, and Queue 4. All the commonly used method required for all the collection is a part of Collection(I). Collections (Class) :- It is a utility class which defines in java.util which defines utility methods for Collection Objects. 1. Methods like sort(), reverse(), max(), min(), shuffle() #Java #CollectionsFramework #LearningJava #Coding
If anyone is interested in developing their skills in Core Java, a quick thought based on my experience that might be helpful. 💬 Here are some tips for developing this skill: 1. Master core Object- Oriented Programming (OOP) principles. 2. Gain a thorough understanding of JVM architecture and memory management. 3. Develop strong understanding of syntax principles. 4. Manually write your code on paper. before implementing it on an IDE 5. Practice daily.
Anybody else who finds it weird to have local variables marked with keyword 'final' in java? Example: public void aSimpleMethod(String argument) { final var someThing = new SomeThing(argument); final var otherThing = new OtherThing(argument); // make call to database using // create event and send it out } IMO, the final is useless in this case.
🚀 Mini Project: Multithreaded File Downloader (Java) Just built a small but powerful console-based downloader to explore Java multithreading and concurrency in real-world use! 💡 What it does: Splits a file into chunks → downloads each in parallel threads → merges into one file ⚙️ 🧵 Concepts used: ExecutorService + Callable for managing threads AtomicLong for progress tracking (thread-safe updates) RandomAccessFile + HTTP Range requests for parallel I/O Live progress bar in the console 💪 Learned: Efficient thread management, synchronization, and I/O operations in Java. Even console-based — it feels like a mini download manager! ⚡ Next up: adding a Swing-based GUI with progress bars and pause/resume options 🎨 #Java #Multithreading #Concurrency #MiniProject #LearningInPublic #JavaDeveloper #DevelopersJourney
🧩 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()
Keep going Shubham Kadam. I suggest to explore Executor Framework as well.