Arrays.asList(int[]) not working [duplicate]

by

When you pass an array of primitives (int[] in your case) to Arrays.asList, it creates a List<int[]> with a single element – the array itself. Therefore contains(3) returns false. contains(array) would return true.

If you’ll use Integer[] instead of int[], it will work.

Integer[] array = {3, 2, 5, 4};

if (Arrays.asList(array).contains(3))
{
  System.out.println("The array contains 3");
}

A further explanation :

The signature of asList is List<T> asList(T...). A primitive can’t replace a generic type parameter. Therefore, when you pass to this method an int[], the entire int[] array replaces T and you get a List<int[]>. On the other hand, when you pass an Integer[] to that method, Integer replaces T and you get a List<Integer>.

More Related Contents:

  1. Arrays.asList() not working as it should?
  2. Array or List in Java. Which is faster?
  3. Convert list to array in Java [duplicate]
  4. Converting array to list in Java
  5. Working with a List of Lists in Java
  6. Java – generate Random range of specific numbers without duplication of those numbers – how to?
  7. Print array without brackets and commas
  8. When to use a List over an Array in Java?
  9. java : Understanding Arrays.asList(T…array) method for primitive types
  10. Converting an int array to a String array
  11. Write a program that takes an array/arraylist of integer and finds longest sub array/arraylist whose entries are equal [closed]
  12. How to add two int array values together?
  13. The best way to print a Java 2D array? [closed]
  14. How do I join two lists in Java?
  15. Java List.add() UnsupportedOperationException
  16. How do I copy a 2 Dimensional array in Java?
  17. What is the Cost of Calling array.length
  18. How to convert object array to string array in Java
  19. Validation of a list of objects in Spring
  20. How to cast from List to double[] in Java?
  21. How to increase an array’s length
  22. Java: Casting from List to List when B implements A?
  23. How does primitive array work with new for each loop in Java?
  24. Create a List of primitive int?
  25. How to manipulate arrays. Find the average. Beginner Java
  26. How to find the only number in an array that doesn’t occur twice [duplicate]
  27. How to convert JSONArray to List with Gson?
  28. Is LinkedList thread-safe when I’m accessing it with offer and poll exclusively?
  29. How to add an element to Array and shift indexes?
  30. Get last element of Stream/List in a one-liner

Leave a Comment