How Can I Declare Generic Methods in Java?

How can I declare and use generic methods in Java?

public <T> void printArray(T[] array) {
    for (T element : array) {
        System.out.println(element);
    }
}

Declaring and using generic methods in Java allows you to write methods that can take parameters of different types. This promotes code reusability and type safety by enabling the compiler to check the types at compile-time.

// Generic method example
public <T> void displayItems(T[] items) {
    for (T item : items) {
        System.out.println(item);
    }
}
// Usage
String[] stringArray = {"Java", "Python", "C++"};
displayItems(stringArray);

Causes

• To create methods that can work universally with any data type.
• To enhance code reusability and maintainability.

Solutions

• Use the syntax <T> before the return type of the method to declare a generic type parameter.
• Invoke the generic method by specifying the type if it's not inferred automatically.

Mistake: Forgetting to place the type parameter before the return type.

Solution: Ensure the type parameter <T> is declared before the return type of the method.

Mistake: Assuming that generic types can be instantiated directly (e.g., new T()).

Solution: Use type parameters as references and avoid trying to create instances of type parameters.