I solved this question using a ArrayList
Not sure if it was the best solution but it worked!
import java.util.ArrayList;
public class Challenge {
public static String[] numInStr(String[] arr) {
ArrayList words = new ArrayList();
for(String i : arr) {
if(i.matches(".*\\d.*"))
words.add(i);
}
String[] j = new String[words.toArray().length];
for(int i = 0; i < j.length; i++) {
j[i] = (String) words.get(i);
}
return j;
}
}