How to Draw ONE Class Diagram for Java, C# and VB?

In this tutorial, we will show you how to present a class model in different programming languages.

Creating a project in specific language

In this section, we will show you how to create a new project in specific programming language. By doing so you can easily select the language-specific types in constructing a class model. Do not worry if you have not been doing this in your production projects. You can switch between languages any time you want. We will show you how to do this in the next section.

1. Select Project > New from the application toolbar.
2. In the New Project window, enter Tutorial as Name.
3. By default, UML is selected to be the Data type set, meaning that you can use the primitive UML data types when constructing your model. Let's say we are going to draw a class diagram for a Java project. Select Java to be the Data type set.
   
4. Click Create Blank Project.

Creating a simple UML class diagram

In this section you will create a class diagram with one class, and several attributes in it. You will be creating the attributes with primitive Java data types.

1. Create a UML class diagram first. You can create a class diagram by selecting Diagram > New from the application toolbar. Select Class Diagram in the New Diagram window and then click Next. Click OK again to create the diagram.
   
2. Click a class User.
   
3. Let's add an attribute name into the class. Right-click on the class and select Add > Attribute from the popup menu.
   
4. name is a (Java) String attribute. You can type name : String to create such an attribute but let's try something different this time. Type name and then click on the diagram background to create a typeless attribute.
   
5. Right-click on the attribute and select Open Specification... from the popup menu.
6. Click on the drop down menu next to the Type field. You can see a list of primitive Java data types available for selection. Now, select String and click OK to confirm.
   
7. Now, create two more attributes age : int and active : boolean. To save time, you can type the name and data type inline without going through the specification window.
   

Presenting class model in another programming language

Now you have a class diagram with Java data types used as attribute types. Your Java developers are happy. Let's entertain the C# developers by presenting the data types in C#.

1. Select Window > Configuration > Configure Programming Language from the application toolbar.
2. The Programming Language window shows the currently selected language, its supported data types and their corresponding display names. We will describe in more detail in a minute. Now, change Language from Java to C#.
   
   The list of data types is updated, and is now longer than before. If you scroll you can see some C# types like uint and ulong, which are not available in Java. So how to read the two columns? Let's check the row for String type. The first and second columns are showing String and string respectively. This means that the original String type (available under Java) will be displayed as string by changing the language to C#.
   
3. Click OK to confirm the change of programming language. You can now see the attributes name is now showing as a C# string, while active is now a C# bool instead of a Java boolean.