Alright fam, let’s take it up a notch! After all the cool stuff Java 9 brought to the table, Java 10 comes in like a breath of fresh air, introducing features that make coding even faster, cleaner, and more efficient. 🎉 Whether you're refining your code or speeding up your apps, Java 10 has got your back!

In this post, we're diving into three standout features:

• Local Variable Type Inference with the shiny new var keyword—goodbye to long type declarations!

• G1 Garbage Collector improvements—because who doesn't want faster, smoother memory management?

• Application Class-Data Sharing (AppCDS)—to speed up the JVM startup even more!

Let’s break down each feature with simple examples to show you how Java 10 is making your dev life easier. Get ready, it's gonna be a fun ride! 💻🔥

Overview

├── 📦 Java 10 (2018)
│ ├── 📝 Local Variable Type Inference
│ │ └── 🗒️ var Keyword
│ ├── ♻️ G1 Garbage Collector Improvements
│ └── 📦 Application Class-Data Sharing (AppCDS)

📝 Local Variable Type Inference – var Keyword

What is it?

So, you know how when you’re writing code, you keep repeating the type of your variables like a broken record? “It’s an int, it’s a String, it’s an ArrayList…” We get it, Java, you love being specific. 😅 But Java 10 says, “What if I could just figure that out for you?” And boom, we got the var keyword!

public class VarExample {
    public static void main(String[] args) {
        var name = "Java 10"; // Java automatically infers this as a String
        var number = 42;      // Java knows this is an int
        var price = 19.99;    // Java sees this as a double

        System.out.println(name);  // Output: Java 10
        System.out.println(number); // Output: 42
        System.out.println(price);  // Output: 19.99
    }
}

Why it’s cool:

• You don’t have to type String, int, or double over and over.

• Java just gets it—it knows what you're trying to do! 🎯

But remember, you still need to give Java a clue when you declare a variable. You can’t just say var and hope for the best! You need to assign it a value, so Java knows what type you mean. Otherwise, it's like trying to buy apples without telling the cashier what color you want. 🍏

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♻️ G1 Garbage Collector Improvements

What is it?

First off, let’s talk about what the Garbage Collector (GC) does. Imagine you’re cleaning up your room. When you’re done playing with toys (or, you know, coding), you need to throw away some stuff to make room for new things. The Garbage Collector in Java is the thing that automatically throws away objects your program no longer needs, so you don’t have to do it yourself. Pretty sweet, right?

In the past, Java’s old GC (like the Parallel Collector) would clean up the trash in one big chunk, causing annoying pauses in your program. Think of it like you’re cleaning your room, but you stop everything to vacuum the whole room in one go. It takes time, and it’s annoying! 🕐

But G1 (Garbage First) came to the rescue, and in Java 10, it got even better. G1 is now faster and more efficient, allowing you to clean up in smaller chunks without the big pauses. It’s like a super-fast cleaner who quietly tidies up in the background while you continue working. 🧹✨

How it works ?

Now, G1 GC divides the heap (where your Java objects live) into smaller regions. These regions can be collected separately, so G1 can focus on cleaning up the “garbage” in just a part of the heap without disturbing the whole program. This means less pause time!

• Young Generation: Newer objects, things that are born and die quickly (like short-lived toys).

• Old Generation: Objects that stick around for longer (like your favorite gaming console).

• G1: G1 smartly decides which regions need cleaning and which don’t, like a professional organizer who knows exactly where the junk is!

G1 is especially helpful in large-scale applications or apps with lots of objects that need to be managed ( For example, If you’re working with an app that has tons of data (think big databases or huge web apps), G1 is like having a cleaning crew that knows exactly where all the clutter is, making it super efficient)

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📦 Application Class-Data Sharing (AppCDS) – Like Sharing a Playlist

What is it?

Alright, picture this: You’re running a party, and everyone is playing the same playlist. Wouldn't it be annoying if each guest had to load the playlist from scratch? Nope! Instead, everyone can just share the playlist, so no one has to waste time loading it. 🎶

AppCDS is like that for Java. When you run multiple Java apps or processes that use the same code, Java can share the class data between them. This makes your apps start faster, like magic, because they don’t need to reload the same code over and over. 🚀

u Need an example ?

Let’s say you’re running a Java-based karaoke app. You don’t want each karaoke session to load the same playlist, right? Instead, you pre-load the classes into a shared data store (like a playlist), and then all your sessions can grab it instantly.

Why it’s awesome:

• Faster Startup: Your app doesn’t need to reload all the classes every time. It can just share the data, making everything quicker to start.

• Memory Efficiency: Instead of each process having its own version of class data, AppCDS shares it, so it’s like using a shared playlist instead of everyone loading their own tracks. 🎶

How Does It Work?

With AppCDS, Java allows you to pre-load class data into a shared cache (like a memory playlist). When you run multiple Java processes that use the same classes, they can access that shared data without having to load it from scratch every time. This is magic for memory and performance.

Example: Using AppCDS in Java

Now, let's look at some code to see how this works. While we can't directly demonstrate this in a few lines of code, here’s how you can enable AppCDS in a Java application

• Step 1: Create a Shared Class Data Archive

First, we need to create the shared class data archive. This is like preparing the karaoke playlist

java -Xshare:dump -cp myapp.jar

This command tells Java to dump all the class data from your app into a shared archive (like creating a playlist of all the classes in myapp.jar).

• Step 2: Use the Shared Data Archive

  Once the data is pre-loaded, every time you run your app, Java will use that shared data archive, skipping the step of loading the same classes over and over.

    java -Xshare:on -cp myapp.jar com.example.MyApp
  

  Here, -Xshare:on tells Java, "Hey, use the shared class data archive we created earlier!"

  Now, your app doesn’t have to load all the classes again. It shares the data, just like everyone enjoying the same karaoke playlist. 🎤✨

now u’d say how AppCDS works in real-world scenarios ?

lemme give you an example

"AppCDS is a lifesaver in environments like microservices, where multiple instances of the same application need to start quickly. Imagine launching tons of Java apps that share the same code—AppCDS helps them get up and running with minimal overhead. 🚀

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And there you have it, folks! Java 10 isn’t just another version—it’s packed with some serious upgrades that make our dev lives smoother, faster, and more fun! Whether it’s the new var keyword simplifying variable declarations, the supercharged G1 Garbage Collector keeping your apps running without hiccups, or the magic of Application Class-Data Sharing speeding up your JVM startup, Java 10 is here to help you code like a pro.

These features aren’t just about saving time—they're about making your code cleaner, more efficient, and ready to take on even the toughest challenges. So go ahead and try them out, and watch your Java apps level up!

Stay tuned for the next article where we'll dive into Java 11 and the next batch of cool features! Until then, happy coding! 💻🔥