Java Programming - MCQ Practice Questions

What does the following generic method signature indicate? public static <T extends Comparable<T>> T findMax(T[] array)

Given: Map<String, ? extends List<?>> map = new HashMap<>(); Which operation is valid?

What is the output of this code? List<String> strings = new ArrayList<>(); List raw = strings; raw.add(123); String str = strings.get(0);

Which statement correctly implements a generic factory method?

What is the compiler-inferred type parameter in this call? List<String> list = Arrays.asList("a", "b", "c");

Consider: public class Pair<T, U> { } Which declaration is invalid?

What does the wildcard in List<?> represent?

Which generic wildcard usage follows the consumer pattern correctly?

What is the compiled signature of this generic method? public <T extends Number & Comparable<T>> void sort(T[] array)

What is the correct way to declare a generic method that accepts a list and returns the maximum element?

Given the declaration: List<List<String>> listOfLists; Which assignment is valid?

What happens when you try to cast a generic object? List<String> strings = (List<String>) getSomeList();

Which of the following represents valid bounded wildcard usage for a method that processes collections?

What is the relationship between generics and arrays in Java?

In the context of generics, what does 'invariance' mean?

How would you correctly use generics in a recursive type bound scenario?

What will be the output of the following code? java List<String> list = new ArrayList<String>(); list.add("Java"); Object obj = list; System.out.println(list.getClass() == obj.getClass());

Which of the following correctly declares a generic method that returns the first element of any collection?

Which declaration is valid in Java Generics?

What does the following generic declaration mean? public <T extends Number & Comparable<T>> T findMax(T a, T b)