What are the Best Methods to Convert an int[] to a List<Integer> in Java?

What are the best methods to convert an int[] to a List<Integer> in Java?

int[] array = {1, 2, 3, 4, 5};
List<Integer> list = Arrays.stream(array).boxed().collect(Collectors.toList());

Converting an `int[]` array to a `List<Integer>` is a common requirement in Java programming. This operation can be accomplished using several methods, each with its unique features and benefits. Below, I will detail the best approaches to achieve this transformation effectively.

// Convert using Java Streams
int[] array = {1, 2, 3, 4, 5};
List<Integer> list = Arrays.stream(array).boxed().collect(Collectors.toList());

// Convert using a simple for-loop
List<Integer> list = new ArrayList<>();
for(int number : array) {
    list.add(number);
}

// Convert using Collections utility
List<Integer> list = new ArrayList<>();
Collections.addAll(list, Arrays.stream(array).boxed().toArray(Integer[]::new));

Causes

• Working with collections instead of arrays can enhance flexibility and functionality in Java applications.
• Java Collections Framework provides more powerful features compared to traditional arrays.

Solutions

• Using Java Streams: This method is concise and utilizes the functional programming style introduced in Java 8.
• Creating a loop: This is a straightforward and traditional approach for converting an array to a list.
• Using the Collections utility: This method wraps the primitive array into a collection.

Mistake: Forgetting to import required classes like `java.util.List`, `java.util.ArrayList`, and `java.util.Arrays`.

Solution: Ensure you have the necessary imports in your Java file to avoid compilation errors.

Mistake: Using `List<int>` instead of `List<Integer>`.

Solution: Remember that Lists in Java cannot contain primitive types, so always use the wrapper classes.