first commit.

src/main/java/xyz/zhouxy/plusone/util/NumberUtil.java

@@ -0,0 +1,29 @@
+package xyz.zhouxy.plusone.util;
+
+/**
+ * NumberUtil
+ *
+ * @author <a href="https://gitee.com/zhouxy108">ZhouXY</a>
+ */
+public class NumberUtil {
+
+    private NumberUtil() {
+        throw new IllegalStateException("Utility class");
+    }
+
+    public static int sum(int... numbers) {
+        int result = 0;
+        for (int number : numbers) {
+            result += number;
+        }
+        return result;
+    }
+
+    public static long sum(long... numbers) {
+        long result = 0;
+        for (long number : numbers) {
+            result += number;
+        }
+        return result;
+    }
+}