Java Question creating a simple library

package anywheresoftware.b4a.sample;

import anywheresoftware.b4a.BA.ShortName;

@ShortName("FirstLib2")
public class FirstLib2 {
    /**
     * test wrapper semplice B4a
     * @param x : numero da moltiplicare
     * @return : x * 2
     */
    public int multiply(int x) {
        return x * 2;
    }
}

#Region  Project Attributes
    #ApplicationLabel: B4A Example
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: unspecified
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim fl As FirstLib2
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.

End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    'Activity.LoadLayout("Layout1")
    Log(fl.multiply(10))
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub