adding files to a jar archive?

I want to add/replace some files in a jar archive, and I have no idea where to start, could someone point me in the right direction?

Jars are archives. So you could use SharpZipLib.

SharpZipLib

Code:

---

Imports ICSharpCode.SharpZipLib.Zip

Public Sub AddFileToJar(ByVal sJarPath As String, ByVal sFileNamePath As String)
    Try
        Dim zipFile As New ZipFile(sJarPath)
        zipFile.BeginUpdate()
        zipFile.Add(sFileNamePath, "filename")
        zipFile.CommitUpdate()
        zipFile.Close()
    Catch ex As Exception
    End Try
End Sub

---

"filename" is optional, but if it's empty then the file will be added with name same as its fullpath.