simple VB code help

Question

I am a java devloper and I wish to convert following code to java can any VB devloper tell me what following does?

    temp8Bit = 0
    temp8Bit = Convert.ToByte(tempRMACode.ToCharArray().GetValue(0))
             + Convert.ToByte((tempRMACode.ToCharArray()).GetValue(7))
    rmaValidationCode += String.Format("{0:X2}", temp8Bit)

tempRMACode is a string

Answer 1

What it's going to do is take the 0th & 7th character from the tempRMACode string, convert those values to Bytes and then add them. Convert is applied to the ASCII value of the character. So Convert.ToByte("A") == 65 the ASCII value of A.

String.Format("{0:X2}", temp8bit) is going to take the numeric value of temp8bit and give you the HEX value. So if you had the number 121 in temp8bit, you'd get 79 in rmaValidationCode.

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Given the following:

Dim temp8bit As Byte
Dim tempRMACode As String = "A234567890"

Dim rmaValidationCode As String = String.Empty

temp8Bit = 0
temp8bit = Convert.ToByte(tempRMACode.ToCharArray().GetValue(0)) _
     + Convert.ToByte((tempRMACode.ToCharArray()).GetValue(7))

Dim a As String = tempRMACode.ToCharArray().GetValue(0)
Dim b As String = tempRMACode.ToCharArray().GetValue(7)

Dim c As Byte = Convert.ToByte(tempRMACode.ToCharArray().GetValue(0))
Dim d As Byte = Convert.ToByte(tempRMACode.ToCharArray().GetValue(7))

rmaValidationCode += String.Format("{0:X2}", temp8bit)

the output is:

temp8bit = 121 or 0x79
a = "A"
b = "8"
c = 65
d = 56
rmaValidationCode = "79"

Answer 2

It is adding the byte values of the 1st and the 8th characters of tempRMACode, then appending it to rmaValidationCode in the format of "0:X2" which is a 2-character hexadecimal representation of the string (temp8Bit).