8 Advanced Java 17+ Tricks to Level Up Your Code

8 Advanced Java 17+ Tricks to Level Up Your Code

Java 17 and newer versions introduce many useful features that allow writing cleaner, safer and more concise code. This article explores some of these modern tricks you should have in your toolkit to improve programming productivity.

1. Leverage Immutable Records to Avoid Boilerplate

Records are a new type of immutable data class that requires way less boilerplate than traditional classes. Define them with just a name and state attributes:

public record Person(String name, int age) {}

Use records to model simple, immutable data structures. They eliminate the need to write explicit constructors, getters, equals and hashCode methods.

2. Restrict Class Hierarchy Extension with Sealed Classes

Sealed classes allow permitting a restricted set of subclasses to extend them:

public abstract sealed class Shape permits Circle, Square, Triangle {}

By sealing the class hierarchy, you can control extendability and enforce architectural rules. Sealed classes also communicate intent clearly.

3. Use Text Blocks for JSON, XML, SQL Without Hassle

Text blocks make working with multi-line strings much easier. Define them using triple quotes “””:

String query = """
    SELECT *
    FROM users
    WHERE age > 18

Text blocks avoid the need for messy escape sequences. Use them for JSON, XML, SQL queries and more.

4. Use Switch Expressions for Cleaner Control Flow

Switch expressions standardize switch syntax using -> and allowing yield statements:

int numLetters = switch (day) {
    case MONDAY, FRIDAY, SUNDAY -> 6;
    case TUESDAY                -> 7;
    default                     -> -1;

Switch expressions prevent fallthrough and make logic flow clearer.

5. Replace instanceOf Checks with Pattern Matching

Pattern matching allows variable assignment within type checks:

if (obj instanceof String s) {
    return s.toUpperCase();

This eliminates messy casts and null checks and improves readability.

Tags: #patternmatching #instanceof #java16

6. Use Records with Sealed Classes for Ultimate Safety

Extending records from sealed classes combines immutability with restricted extendability for improved type safety:

public abstract sealed class Permit
   permits ConcretePermit {}

public record ConcretePermit() extends Permit {}

Use this powerful combo to enforce architectural rules safely.

7. Simplify Code with Helpful New Library APIs

Java 17 adds many conveniences like List.of, Set.of and Map.of to succinctly create collections:

var names = List.of("John", "Jane");

Stream.toList, Vector API and more also simplify code.

8. Use var Keyword for Local Variable Type Inference

The var keyword declares the type based on initialization:

var str = "Hello";// String str

Avoid explicitly repeating types with var to reduce clutter.

So there you have it – my top 9 features to level up your Java coding skills! Adopting modern Java patterns promotes cleaner code. Use records, sealed classes, text blocks, helpful exceptions, switch expressions, pattern matching, new APIs and the var keyword to write robust programs with less effort.

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