Why do I get an UnsupportedOperationException when trying to remove an element from a List?

Question

I have this code:

public static String SelectRandomFromTemplate(String template,int count) {
   String[] split = template.split(\"|\");
   List         


        

Answer 1

The issue is you're creating a List using Arrays.asList() method with fixed Length meaning that

Since the returned List is a fixed-size List, we can’t add/remove elements.

See the below block of code that I am using

This iteration will give an Exception Since it is an iteration list Created by asList() so remove and add are not possible, it is a fixed array

List words = Arrays.asList("pen", "pencil", "sky", "blue", "sky", "dog"); 
for (String word : words) {
    if ("sky".equals(word)) {
        words.remove(word);
    }
}   

This will work fine since we are taking a new ArrayList we can perform modifications while iterating

List words1 = new ArrayList(Arrays.asList("pen", "pencil", "sky", "blue", "sky", "dog"));
for (String word : words) {
    if ("sky".equals(word)) {
        words.remove(word);
    }
}