import java.util.ArrayList;
import java.util.Collections;
public class odd {
public static void main(String[] args) {
int x = 20;
ArrayList<Integer> odd = new ArrayList<Integer>();
ArrayList<Integer> even = new ArrayList<Integer>();
while (x > 0) {
if (x % 2 != 0) {
odd.add(x);
} else {
even.add(x);
}
x--;
}
Collections.sort(odd);
Collections.sort(even);
for (int i = 0; i < odd.size(); i++) {
System.out.println(odd.get(i));
}
for (int i = 0; i < even.size(); i++) {
System.out.println(even.get(i));
}
System.out.println(even + "evens" + odd + "odds");
}
private odd() {
}
}
but if you don't understood,