Pull Request: CX_Moataz_240_compiler_compile_3.4

<h3>Issue: #240</h3> 
- <b>Differentiate between warning and error messages</b>

Reviewers: @mohamedsaeed93 @KhaledHelmy @MussabElDash @ahmedhagii 

<b><i>Sample code:</i></b>
```
import java.util.*;
public class CoolSoft {
	public static void main(String [] args) {
		LinkedList l = new LinkedList();
		l.add(5);
	}
}
```