java list addAll function [duplicate]

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• Why I get UnsupportedOperationException when trying to remove from the List? 11 answers

New to java. I created two List objects and tried to add the second list to the first one, code as below.

import java.util.*;

public class t {
    public static void main(String[] args){

        String[] things = {"a", "b", "c", "d", "e", "f"};
        List<String> list1 = Arrays.asList(things);

        String[] things2 = {"g", "h", "i", "j"};
        List<String> list2 = Arrays.asList(things2);

        list1.addAll(list2);
    }
}

it can successfully compile, but when I run it, error information as below:

I am wondering what has happened here. Why I cannot use addAll function. Since two lists are both declared to hold String types.