Imports System.Text.RegularExpressions
Module Module1
Sub Main()
Dim s As String = "java jar vb ja jaa j a jjb"
Dim matches As MatchCollection = Regex.Matches(s, "j\w+a")
For Each m As Match In matches
For Each substr As Capture In m.Captures
Console.WriteLine("{0} : {1}", substr.Index, substr.Value)
Next
Next
End Sub
End Module
' run:
'
' 0 : java
' 15: jaa