为什么重载的方法不打印

public class MaxMethod {

// 方法重载

public void max(double a, double b) {

}

public void max(float a, float b) {

float max;

if (a > b) {

max = a;

} else {

max = b;

}

System.out.println(" " + a + " and " + b + "  的最大值 " + max);

}

public static void main(String[] args) {

MaxMethod md = new MaxMethod();

int a = 4, b = 5;

md.max(a, b);

md.max(9.8, 7.8);

md.max(8.9, 5.6);

}

}