Practice Questions

Which statement about String objects is true?

A. They are mutable B. They are thread safe but mutable C. They are immutable D. They cannot be compared

What is the output of this code? var list = List.of(1, 2, 3); list.stream().filter(x -> x > 1).forEach(System.out::print);

A. 123 B. 23 C. 12 D. Compilation error

Which interface is a functional interface?

A. Runnable B. Comparator C. Both A and B D. None

What happens if an exception is thrown inside a try with resources block?

A. Resources are not closed B. Resources are closed automatically C. Program crashes immediately D. Compiler error

Which collection does not allow duplicates?

A. List B. Set C. Map D. Queue

What is the default value of a boolean instance variable?

A. true B. false C. null D. 0