Generic Class

A Generic Class allows the definition of classes with a placeholder for a type, enabling reusability and type safety. The type is specified when the object is instantiated.

Syntax

class Box<T> {
    T item;
    void set(T item) { this.item = item; }
    T get() { return item; }
}

Usage

public class Main {
    public static void main(String[] args) {
        Box<Integer> intBox = new Box<>();
        intBox.set(100);
        System.out.println("Integer Value: " + intBox.get());

        Box<String> strBox = new Box<>();
        strBox.set("Hello Generics");
        System.out.println("String Value: " + strBox.get());
    }
}

Multiple Type Parameters

class Pair<K, V> {
    K key;
    V value;

    Pair(K key, V value) {
        this.key = key;
        this.value = value;
    }

    K getKey() { return key; }
    V getValue() { return value; }
}

Benefits

  • Reduces code duplication
  • Type-safe data structures
  • Easier to debug and maintain

🔗 Related Notes