Java – recursive method: why do I need a return statement?

Just to practice recursion, I wrote a classic introduction to recursion - a function that checks whether a given string is a palindrome

My question is: in the first if statement, why do I have to write to return palchecker (...) instead of just palchecker (...)? In my opinion, the function should not have the first return statement But from the test, I know it's not true, but I don't know why

(by the way, the printed statements are right there, so I can see what happens during the test. I like to see each execution line.)

public static boolean palChecker(String s){
    if ( s.charAt(0)==s.charAt(s.length()-1) && s.length()>1){
        System.out.println(s);
        return palChecker(s.substring(1,s.length()-1)); //why do i need the return here?
    }
    else if (s.length()==1 || s.length()==0){
        System.out.println(s);
        return true;
    }
    return false;
}

Solution

You need to return the final value returned by palchecker

The definition of a Java function is that it always returns a value... Even if it is the deepest chain in recursion, and finally brings true or false to the top