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Wildcards

The result of the code

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What will be the result of the following code compilation and execution:

import java.util.ArrayList;
import java.util.List;

public class Application {
  
  public static void main(String[] args) {
    System.out.println(wildcardsTest(new ArrayList<>()));  
  }
  
  public static Integer wildcardsTest(List<? extends Integer> numbers) {
    numbers.add(null);
    return numbers.get(0);
  }

}

Select one option from the list

Runtime error on "numbers.add(null);"

null printed to standard output

Compile-time error on "return numbers.get(0);"

Compile-time error on "numbers.add(null);"

NullPointerException is thrown

Runtime error on "return numbers.get(0);"

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