fix(guide): simplify directory structure

guide/english/java/instanceof-operator/index.md

@@ -0,0 +1,14 @@
+---
+title: instanceof Operator
+---
+# `instanceof` operator
+
+The `instanceof` operator allows you to check the validity of a `IS A` relationship. If at any point of time, we are not sure about this and we want to validate this at runtime, we can do the following:
+
+```java
+//assuming vehicle is an instance of Class `Car` the expression inside the 'if' will  return true
+if(vehicle instanceof Car){
+    //do something if vehicle is a Car
+}
+```
+ **Note**: If you apply the instanceof operator with any variable that has null value, it returns false.