"I would use String.concat only if I was sure of non-null values," Elena replied, grabbing a marker and writing on the whiteboard. "But for safety, I’d switch to a StringBuilder or handle the nulls explicitly. In Java 8 and above, the cleanest way is using Objects.toString or explicit checks."
Inheritance, interfaces, and abstract classes. testdome java questions and answers
import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentMap; "I would use String
public class TV implements Remote public void turnOn() System.out.println("TV ON"); public void turnOff() System.out.println("TV OFF"); " Elena replied
Input: [100, 4, 200, 1, 3, 2] → Output: 4 (because [1,2,3,4] is the longest streak).