MinMaxGener.java

// GMH-MinMaxGener/MinMaxGener.java
 
class GenArr<T extends Comparable<T>> {
    private T[] arr;
    private T   min, max;

    public GenArr(T[] arr) {
        if (arr == null || arr.length == 0)
            throw new IllegalArgumentException();
        min = arr[0];
        max = arr[0];
        for (int i = 1; i < arr.length; ++i) {
              // we can use compareTo, as we know
              // that T extends Comparable
              // (and the compiler has checked it)
            if (arr[i].compareTo(min) < 0) min = arr[i];
            if (arr[i].compareTo(max) > 0) max = arr[i];
        }
    }
    public T getMin() { return min; }
    public T getMax() { return max; }
}

public class MinMaxGener {
    public static void main(String[] args) {
        GenArr<Integer> mnmxI =
            new GenArr<>(new Integer[]{3, -2 , -7, 2});
        GenArr<String> mnmxS =
            new GenArr<>(new  String[]{"A", "Z", "C"});

        System.out.println("I - min = " + mnmxI.getMin() +
                           "\nI - max = " + mnmxI.getMax());
        System.out.println("S - min = " + mnmxS.getMin() +
                           "\nS - max = " + mnmxS.getMax());
    }
}