Question

I have this method which takes a varargs of Strings, creates a List out of it, and then tries to remove the first element of the list.

public void importFrom(String... files) {
    List<String> fileList = Arrays.asList(files);

    String first = fileList.remove(0);
    // other stuff
}

But as soon as remove gets called, an UnsupportedOperationException is thrown. My guess is that the return List-Type does not support the remove method. Am I correct? What alternatives do I have?

Answer 1

Arrays.asList only provides a thin wrapper around an array. This wrapper allows you to do most operations on an array using the List API. A quote from the JavaDoc:

Returns a fixed-size list backed by the specified array. […]
This method acts as bridge between array-based and collection-based APIs […]

If you really want to remove something, then this might work:

List<String> realList = new ArrayList<String>(Arrays.asList(stringArray));

This one creates a real ArrayList (which supports remove) and fills it with the contents of another list which happens to be the wrapper around your String[].