B4J Question How convert from vba to B4j code?

Sub decrypt(key As String, src As String) As String
    Dim KeyPos As Int = -1, KeyLen As Int, SrcAsc As Int, dest As String, offset As Int, TmpSrcAsc As Int, SrcPos As Int
    KeyLen = key.Length
    offset = Bit.ParseInt(src.SubString2(0, 2), 16)
    For SrcPos = 2 To src.Length - 1 Step 2
        SrcAsc = Bit.ParseInt(src.SubString2(SrcPos, SrcPos + 2).Trim, 16)
        If KeyPos < KeyLen - 1 Then KeyPos = KeyPos + 1 Else KeyPos = 0
        TmpSrcAsc = Bit.And(0xff, Bit.Xor(SrcAsc, Asc(key.CharAt(KeyPos))))
        If TmpSrcAsc <= offset Then
            TmpSrcAsc = 255 + TmpSrcAsc - offset
        Else
            TmpSrcAsc = TmpSrcAsc - offset
        End If
        dest = dest & Chr(TmpSrcAsc)
        offset = SrcAsc
    Next
    Return dest
End Sub