Bug? Matcher.Find is reset once first examined.

Public Sub Extract( strPattern As String, strText As String, blnCaseSensitive As Boolean, intExtractGroup As Int) As String
    Dim m As Matcher
    If blnCaseSensitive Then
        m = Regex.Matcher(strPattern, strText)       
    Else
        m = Regex.Matcher2(strPattern, Regex.CASE_INSENSITIVE, strText)
    End If
    Log(m.GroupCount)
    If m.Find = True Then Log("A")
    If m.Find = True Then Log("B")
    If m.Find = True Then Log("C")
    If m.Find = True Then Log("D")
    If m.Find = True Then Return m.Group(intExtractGroup)
    ' Return an empty string if pattern not found
    Return ""
End Sub

#Region  Service Attributes
    #StartAtBoot: False
    #ExcludeFromLibrary: 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.

End Sub

Sub Service_Create
    'This is the program entry point.
    'This is a good place to load resources that are not specific to a single activity.

End Sub

Sub Service_Start (StartingIntent As Intent)
    Log("Valid email format = " & Validate_Email("Hewlett-Packard@HPforyou.hp.com"))
End Sub

'Return true to allow the OS default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
    Return True
End Sub

Sub Service_Destroy

End Sub

Sub Validate_Email(EmailAddress As String) As Boolean
    Dim MatchEmail As Matcher = Regex.Matcher("^(?i)[a-z0-9!#$%&'*+/=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+/=?^_`{|}~-]+)*@(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])$", EmailAddress)

    Log("Status=" & MatchEmail.Find)
    If MatchEmail.Find = True Then
        Log(MatchEmail.Match)
        Return True
    Else
        Log("Oops, please double check your email address...")
        Return False
    End If
End Sub