YAGNI, KISS, and DRY

YKD.md

3 Simple Software Principles: YAGNI, KISS, and DRY

Three useful software principles are YAGNI, KISS, and DRY.

YAGNI: You Aren’t Gonna Need It

Build only what you need right now. Don’t add features just because you might need them later.

public class User {
    private String name;
    private int age;

    public User(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

Avoid adding unnecessary fields “just in case.”

KISS: Keep It Simple

Write code that is easy to read and understand. Simple code is easier to maintain and debug.

public static List<Integer> getEvenNumbers(List<Integer> numbers) {
    return numbers.stream()
            .filter(number -> number % 2 == 0)
            .toList();
}

Don’t make code more complicated than necessary.

DRY: Don’t Repeat Yourself

Avoid writing the same logic in multiple places. Put repeated logic in one reusable method.

public static String getProductName(Product product) {
    return product.getName();
}

public static double getProductPrice(Product product) {
    return product.getPrice();
}

A better approach is to access product properties through the object’s existing methods instead of creating unnecessary duplicate logic.

public class Product {
    private String name;
    private double price;

    public String getName() {
        return name;
    }

    public double getPrice() {
        return price;
    }
}

Conclusion

• YAGNI: Build only what you need.
• KISS: Keep your code simple.
• DRY: Avoid repeating code.

Following these principles helps you write cleaner and more maintainable software.