How to create a generic array in Java

Generic arrays in Java are described as arrays with parameterized types, allowing the arrays to operate on many data types while preserving each data type safety. Directly generating arrays with generic types is not supported in Java because of how arrays and generics are constructed and type erasure. We can bypass this restriction by making an array of objects and casting the components to the required generic type.

@SuppressWarnings("unchecked")
//Define a class with generic type parameter
public class genericArray<T> {
    
    //Declare an array
    private T[] arr;
    
    //Parameterized Constructor
    public genericArray(int size) {
        arr = (T[]) new Object[size];
    }
    
    //Getter & Setter
    public void set(int index, T value) {
        arr[index] = value;
    }
    public T get(int index) {
        return arr[index];
    }
    //The main class
    public static void main(String[] args) {
        //array declaration
        genericArray<Integer> array = new genericArray<>(4);
        genericArray<String> array1 = new genericArray<>(2);
        System.out.println("Array 1:");
        array.set(0, 1);
        array.set(1, 2);
        array.set(2, 3);
        array.set(3, 4);
        
        System.out.println(array.get(0));
        System.out.println(array.get(1));
        System.out.println(array.get(2));
        System.out.println(array.get(3));
        System.out.println("----------------------------------------------");
        
        System.out.println("Array 2:");
        array1.set(0, "Hello");
        array1.set(1, "Educative!!");
         System.out.println(array1.get(0));
        System.out.println(array1.get(1));
    }
}

Implementation of generic array

Explanation

Line 1: Here, we have the @SuppressWarnings("unchecked") annotation to stop compiler warnings about unchecked type casting.
Line 4: This line defines a class genericArray with the generic type parameter T.
Line 7: This line declares an array to store generic elements.
Lines 10–12: Here, we have a parameterized constructor that initializes the array with a given size.
Lines 15–21: These lines define the getter and setter functions for the genericArray.
Lines 26–27: These lines create an instance genericArray with String and Integer as the generic types.
Lines 29–46: These lines use setter and getter to initialize and retrieve the arrays, and then print values from the arrays.

Limitations

This approach has some limitations and potential problems: