mukundanebritah

[mukundanebritah]

java- single constructor Vs multiple constructors

❌ The Multiple Constructor Example

public class Human {

private String name;

private int limbs;

private String skinColor;

public Human(String name) {

this(name, 4, "Unknown"); // Magic numbers!

}

public Human(String name, int limbs) {

this(name, limbs, "Unknown");

}

Why this fails: Hidden assumptions (Why default limbs = 4?), duplicate validation (What if limbs < 0?), brittle maintenance (Adding bloodType breaks all constructors)

✅ The Single Constructor Solution

public class Human {

private final String name; // Required

private final int limbs; // Required

private final String skinColor; // Required

public Human(String name, int limbs, String skinColor) {

Objects.requireNonNull(name);

if (limbs < 0) throw new IllegalArgumentException("Limbs cannot be negative");

this.name = name;

this.limbs = limbs;

this.skinColor = skinColor;

}

}

benefits: No magic defaults -Forces explicit values, validation in one place - Fail fast principle, immutable by design - Thread-safe and predictable

Handling Optional Fields: The Builder Pattern For complex cases (like optional eyeColor), use a Builder:

Human britta = new Human.Builder("Britta", 4)

.skinColor("dark")

.eyeColor("blue")

.build();

Why Builders win: Clear defaults (`.skinColor("dark")` vs. constructor overloading), flexible (Add new fields without breaking changes), readable (Named parameters > positional args)

When Multiple Constructors Make Sense

Simple value objects (e.g., Point(x, y)), framework requirements (JPA/Hibernate no-arg constructor), most classes need just one constructor. Pair it with: factory methods for alternative creation logic and builders for optional parameters

This approach eliminates: hidden defaults, validation duplication and maintenance nightmares Do you prefer single or multiple constructors? Have you been bitten by constructor overload? Share your war stories in the comments!

#Java #CleanCode #OOP #SoftwareDevelopment #Programming