add documentation for the famix java metamodel

moose-wiki/Users/famix-java/famix-java.md

@@ -6,18 +6,26 @@ title: 'Famix Java'
 toc: true
 ---
 
-> This is a work in progress page that tries to help beginners. Do not hesitate to contact us for more information
-
 Famix Java is the metamodel included in Moose used to represent any Java application.
 As you can imagine, the metamodel is rather than complicated.
 For instance, Famix Java uses a lot the [traits concept](/Developers/predefinedEntities).
 
-We will present here some incorrect, but simplify and useful view to enable beginners to use Famix Java.
+We will present here some incorrect, but simple and useful views to enable beginners to use Famix Java.
 
 ## Class neighborhood
 
 ![Parametric schema](./img/class-neighborhood.drawio.svg){: .img-fluid .img-center }
 
+Most of the time, you only need to understand these core entities to start analyzing your application.
+You can retrieve the main concepts: Packages, Classes, Methods and Attributes.
+You'll notice that relation between Methods and Attribute is made from the Access reification, as well as Method invocation through the Invocation concept.
+
+The complete meta-model is not represented here.
+For instance, it also includes LocalVariable, Parameters, ParametricClasses and a lot more.
+
+> In Moose, all relation are bi-directional.
+> We added the arrow on relation based on common usage, but you can always go the other way around.
+
 ## Type neighborhood
 
 ```mermaid!
@@ -37,6 +45,14 @@ classDiagram
     FamixJavaInterface <|-- FamixJavaParametricInterface
 ```
 
+Types are the central pieces of Object-Oriented programming languages.
+In the FamixJava meta-model, all types are subclass of the FamixJavaType concept.
+In addition to the FamixJavaClass previously described, we represent Interface, Enum, PrimitiveType, ParameterType, and Wildcard.
+
+ParameterType and Wildcard are mostly used when looking for parametric type.
+
+Primitive type are made to represent `int`, `double`, `long`, *etc.* in Java, as well as `void` if necessary.
+
 ### Focus on Parametric Type
 
 Parametric types are probably the most hard to understand.