Added 8 solutions

Java/Exception Handling/Java Exception Handling/Solution.java

@@ -8,7 +8,9 @@ import java.util.Scanner;
 class MyCalculator {
     long power(int n, int p) throws Exception {
         if (n < 0 || p < 0) {
-            throw new Exception("n and p should be non-negative");
+            throw new Exception("n or p should not be negative.");
+        } else if (n == 0 && p == 0) {
+            throw new Exception("n and p should not be zero.");
         } else {
             return (long) Math.pow(n, p);
         }