added java backend (logic only)

test.java

@@ -0,0 +1,17 @@
+package backendAlex;
+
+class test {
+    public static void main(String[] args) {
+        UrlShortener url = new UrlShortener();
+        //String shortUrl = url.getShortUrl("longUrlTest2");
+        //System.out.println(shortUrl);
+
+        //String longUrl = url.getLongUrl(shortUrlTest3);
+        //System.out.println(longUrl);
+        String shortUrl = url.getShortUrl("longUrlTest6");
+        System.out.println(shortUrl);
+
+        //url.printJson();
+    }
+    
+}