Good Article : String concatenation in Java 9

There is a great article that describes the differences of String concatenation in Java 8 and 9.

String concatenation in Java 9 (part 2): Conversion confusion

Before reading, what do you think the log in Java 9?

public class Alice { 
    String[] wonders = new String[]{“ cats”, “ eat”, “ bats”}; 
    int wonderIndex = 0; 
    @Override public String toString() { 
        return wonders[wonderIndex++]; 
    } 
    public static void main(String[] args) { 
        Alice alice = new Alice(); 
        System.out.println(“Do” + alice + alice + alice + ‘?’); 
    } 
}

You will get the answer and understand why after reading it.