Quiz: Java Strings

5 questionsNo time limitPass: 60%+10 XP on first pass

Why == fails for strings, how the string pool works, the most-used String methods, StringBuilder for fast building, and string interview programs.

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Question 1

What does this print?

public class Main {
    public static void main(String[] args) {
        String a = "hi";
        String b = new String("hi");
        System.out.println(a == b);
    }
}

truefalsehiError

Question 2

What does this print?

public class Main {
    public static void main(String[] args) {
        System.out.println("Placement".substring(2, 5));
    }
}

lacaceacemPla

Question 3
Which is the fastest choice to build a long string in a single-threaded loop?
String with +StringBufferStringBuilderString.concat
Question 4
Why are Java Strings immutable? (pick the best reason)
To use less memory per characterSo they can be safely shared (string pool) and are thread-safeBecause Java has no arraysTo make them faster to change

Question 5

What does this print?

public class Main {
    public static void main(String[] args) {
        String s = "abc";
        s.concat("def");
        System.out.println(s);
    }
}

abcdefabcdefError