How to Return Multiple Objects from a Method in Java

Java, being a statically typed language, does not allow you to return multiple objects directly from a method. However, there are several techniques to achieve this. In this article, we will explore various methods to return multiple objects from a method in Java, including using classes, arrays, lists, built-in classes, and third-party libraries.

1. Using a Custom Class

One straightforward way is to create a custom class to hold the two objects you want to return. This method is flexible and allows you to encapsulate the objects with additional methods and properties.

public class Pair {
    private Object first;
    private Object second;
    public Pair(Object first, Object second) {
          first;
          second;
    }
    public Object getFirst() {
        return first;
    }
    public Object getSecond() {
        return second;
    }
}

Here is how you can use it to return a pair of objects:

public Pair returnTwoObjects() {
    Object obj1  new Object(); // replace with actual object
    Object obj2  new Object(); // replace with actual object
    return new Pair(obj1, obj2);
}

2. Using an Array or a List

If the objects are of the same type, using an array or a list is another viable approach. This method is simple and suitable for quick solutions.

// Returning an array
public Object[] returnTwoObjects() {
    Object obj1  new Object(); // replace with actual object
    Object obj2  new Object(); // replace with actual object
    return new Object[]{obj1, obj2};
}

Alternatively, you can use a List for a more dynamic approach:

// Using List
public ListObject returnTwoObjects() {
    Object obj1  new Object(); // replace with actual object
    Object obj2  new Object(); // replace with actual object
    return List.of(obj1, obj2);
}

3. Using a Built-in Pair Class

For Java 8 and above, the class provides a convenient way to return pairs. This is a built-in class that encapsulates two objects and provides a simple API.

import ;
public SimpleEntryObject, Object returnTwoObjects() {
    Object obj1  new Object(); // replace with actual object
    Object obj2  new Object(); // replace with actual object
    return new SimpleEntry(obj1, obj2);
}

4. Using a Tuple Library

For more complex cases, you can use third-party libraries such as Apache Commons Lang or Vavr, which provide tuple classes.

import ;
import ;
public Tuple2Object, Object returnTwoObjects() {
    Object obj1  new Object(); // replace with actual object
    Object obj2  new Object(); // replace with actual object
    return Tuple.of(obj1, obj2);
}

Summary

Choosing the right method depends on the nature of your objects, the type safety required, and the availability of third-party libraries in your project. Each method has its own advantages and use cases, so it’s a good idea to consider these factors before selecting a solution.

Incorporating these techniques into your Java code can significantly improve the structure and maintainability of your applications, making it easier to handle complex data without making your methods overly complex or hard to understand.