关于递归的理解

代码如下：

// 递归练习
public class recursionTest {

    public static int getMax(int[] arr,int l,int r){
        if(l == r){
            return arr[l];
        }
        int median = (int)(l + r)/2;
        System.out.println(arr[median]);
        int leftMax = getMax(arr,l,median);
        int rightMax = getMax(arr,median+1,r);
        return Math.max(leftMax,rightMax);
    }

    public static int[] createAarray(int maxvalue,int number){
        int[] arr = new int[(int)((number+1) * Math.random())];
        for (int i = 0;i < arr.length ; i++){
            arr[i] = (int)(Math.random() * (maxvalue + 1));
        }
        return arr;
    }

    public static int[] copyArray(int[] arr){
        int[] temp = new int[arr.length];
        for (int i = 0; i < arr.length; i++) {
            temp[i] = arr[i];
        }
        return temp;
    }

    public static void main(String[] args) {
        int[] arr = createAarray(100,10);
        for (int i = 0; i < arr.length; i++) { System.out.print(arr[i]+ " "); }
        System.out.println();
        int maxvalue = getMax(arr,0,arr.length-1);
        System.out.println(maxvalue);
    }

}