From f9f816514cc981fc78b5d2f0bb79d09d8ca2e11f Mon Sep 17 00:00:00 2001
From: Raymart Evangelista <44074441+revang10@users.noreply.github.com>
Date: Wed, 26 Dec 2018 15:26:34 -0800
Subject: [PATCH] Update index.md (#26358)

* Update index.md

Added statements to visualize interfaces differently.

* Formatting changes
---
 guide/english/java/interfaces/index.md | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/guide/english/java/interfaces/index.md b/guide/english/java/interfaces/index.md
index bf55cff9ae6..3a226a6a8cc 100644
--- a/guide/english/java/interfaces/index.md
+++ b/guide/english/java/interfaces/index.md
@@ -3,7 +3,11 @@ title: Interfaces
 ---
 # Interfaces
 
-Interface in Java is a bit like the Class, but with a significant difference : an `interface` can _only_ have method signatures, fields and default methods. Since Java 8, you can also create [default methods](https://docs.oracle.com/javase/tutorial/java/IandI/defaultmethods.html). In the next block you can see an example of interface :
+Interface in Java is a bit like the Class, but with a significant difference : an `interface` can _only_ have method signatures, fields and default methods. Since Java 8, you can also create [default methods](https://docs.oracle.com/javase/tutorial/java/IandI/defaultmethods.html). 
+
+Classes that  implement an interface are thought to be signing a contract and agreeing to perform the specific behaviors listed in the interface. If the classes that implement an interface do not implement all the methods of the interface, then such a class needs to be defined as `abstract`.
+
+In the next block you can see an example of interface :
 
 ```java
 public interface Vehicle {
@@ -46,7 +50,7 @@ Vehicle tesla = new Car();
 tesla.start(); // starting engine ...
 ```
 
-An Interface **can not** contain a constructor methods,therefore,you **can not** create an instance of an Interface itself. You must create an instance of some class implementing an Interface to reference it. Think of interfaces as a blank contract form, or a template.
+An Interface **can not** contain a constructor methods,therefore,you **can not** create an instance of an Interface itself. You must create an instance of some class implementing an Interface to reference it. Think of interfaces as a blank contract form, or a template. 
 
 What can you do with this feature? Polymorphism! You can use only interfaces to refer to object instances!