Create a list of item on a single line, then query list to see if item exists, without receiving unchecked conversion warning in Java

Question

I want a list of things, and then I want to test the list to see if an item exists:

Here is my example snippet:

    String[] handToolArray = {"pliers", "screwdriver", "tape measure"}; 
    List<String> handToolList = new ArrayList<String>( Arrays.asList(handToolArray));

    if (handToolList.contains("pliers")){
        System.out.println("I have pliers");
    } else {
        System.out.println("I don't have pliers");
    }

In the second line, the Arrays.asList(handToolArray) generates:

"Type safety: The expression of type List needs unchecked conversion to conform to Collection<? extends String>"

Question: Is there a better way to create then query the list, that is succinct and does not require unchecked warnings to be suppressed?

Answer 1

You can do it without explicitly constructing an array (arrays are still used by varargs).

List<String> handToolList = Arrays.asList("pliers", "screwdriver", "tape measure");

Answer 2

First of all, I do not get the type safety warning, and neither should you. What Java compiler are you using?

Arrays.asList already creates an ArrayList (backed by the original array), so if you do not need a copy, you can just do

 List<String> handToolList =  Arrays.asList(handToolArray);

Also note that something like Apache Commons Lang ArrayUtils has functions to check if an element exists in an array directly:

if (ArrayUtils.exists(handToolArray , "pliers"))

Answer 3

Note that the List interface defines the indexOf() method which you can use to check if something exist:

List<String> list = Arrays.asList(handTools);
if(list.indexOf("pliers!") != -1) {
  System.out.println("We have pliers.");
}
else {
  System.out.println("We do not have any pliers.");
}