Did you know ?

While Java is known for int, String, and other explicit data types… You can actually use var in Java! 🤯

Yes, Java introduced var in Java 10, and it’s a game-changer for developers who love clean, readable code!

I know, we all think of Java as the language where you have to spell everything out… String this, ArrayList that. But since Java 10, we’ve had this awesome little shortcut.
Let me show you what I mean:

// without using var
ArrayList<String> names = new ArrayList<>();
LinkedHashMap<Integer, String> userMap = new LinkedHashMap<>();
// with var
var names = new ArrayList<String>();
var userMap = new LinkedHashMap<Integer, String>();
// without using var
ArrayList<String> names = new ArrayList<>();
LinkedHashMap<Integer, String> userMap = new LinkedHashMap<>();

// with var
var names = new ArrayList<String>();
var userMap = new LinkedHashMap<Integer, String>();
// without using var
ArrayList<String> names = new ArrayList<>();
LinkedHashMap<Integer, String> userMap = new LinkedHashMap<>();

// with var
var names = new ArrayList<String>();
var userMap = new LinkedHashMap<Integer, String>();

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Now before you ask – nope, this isn’t making Java dynamically typed like JavaScript. It’s just syntactic sugar. Java is still doing all its strict type checking behind the scenes. You’re just saving yourself some typing and making your code a bit cleaner to read.

A few quick things to keep in mind:

• You can only use var for local variables
• You have to initialize the variable right away
• It won’t work with null values (the compiler needs to know the type!)

What do you all think? Are you already using var in your Java code? Let me know in the comments!

原文链接： Did you know ?