chore(Java): add shell sort (#262)

algorithms/Java/README.md

@@ -1,4 +1,4 @@
-# Python
+# Java
 
 ## Arrays
 
@@ -45,6 +45,7 @@
 5. [Merge Sort](sorting/merge-sort.java)
 6. [Quick Sort](sorting/quick-sort.java)
 7. [Selection Sort](sorting/selection-sort.java)
+8. [Shell Sort](sorting/shell-sort.java)
 
 ## Stacks
 

algorithms/Java/sorting/shell-sort.java

@@ -0,0 +1,19 @@
+public class ShellSortApp {
+    public static void main(String[] args) {
+	    int[] intArray = { 20, 35, -15, 7, 55, 1, -22 };
+        for (int gap = intArray.length / 2; gap > 0; gap /= 2) {
+            for (int i = gap; i < intArray.length; i++) {
+                int newElement = intArray[i];
+                int j = i;
+                while (j >= gap && intArray[j - gap] > newElement) {
+                    intArray[j] = intArray[j - gap];
+                    j -= gap;
+                }
+                intArray[j] = newElement;
+            }
+        }
+        for (int i = 0; i < intArray.length; i++) {
+            System.out.println(intArray[i]);
+        }
+    }
+}