The idea behind No loop loop, or to use the correct term "recursion", is to illustrate a way to create a loop in Java, but without making use of regular loops like for-, for each-, while-, do while-loops.

The way this loop works is by a call of the firstMethod, passing our argument aNumber to it.
Next, firstMethod checks, if a condition (aNumber <= 0) is given or not. If aNumber is > 0 nothing happens, and our argument aNumber will be passed to secondMethod.
Now, secondMethod subtracts 1 from aNumber and passes it back again to firstMethod, which will end the program as soon as aNumber reaches the value of <= 0.

Please note: recursion can have significant memory usage implications, as each recursive call requires additional stack space, and can result in a StackOverflowError if the recursion depth gets too large.

public class Methods_Loop {
    public static void main(String[] args) {
        int aNumber = 10;
        firstMethod(aNumber); // Inputting the number
    }

    public static void firstMethod(int aNumber) {
        System.out.println("firstMethod: " + aNumber);
        if (aNumber <= 0) {
            return; // This will end your program
        }

        secondMethod(aNumber);
    }

    public static void secondMethod(int aNumber) {
        aNumber = aNumber - 1;
        System.out.println("secondMethod: " + aNumber);
        firstMethod(aNumber);
    }

}