Base64 Encoding in Java vs HttpServerUtility.UrlTokenEncode in C#

I'm having a trouble while I tried to encode a String in Java.

I have the follwing code in C#, and the string Bpz2Gjg01d7VfGfD8ZP1UA==, when I execute C# code I'm getting:

QnB6MkdqZzAxZDdWZkdmRDhaUDFVQT090

public static void Main(string[] args)
{
    string strWord = "Bpz2Gjg01d7VfGfD8ZP1UA==";
    byte[] encbuff = Encoding.UTF8.GetBytes(strWord);
    string strWordEncoded = HttpServerUtility.UrlTokenEncode(encbuff);
    Console.WriteLine(strWordEncoded);
}

I'm trying to replicate the previous code in Java, in the first attempt I used the javax.xml.bind.DatatypeConverter Class:

public static void main(String[] args) {
    String strWord = "Bpz2Gjg01d7VfGfD8ZP1UA==";
    byte[] encbuff = strWord.getBytes(StandardCharsets.UTF_8);
    String strWordEncoded = DatatypeConverter.printBase64Binary(encbuff);
    System.out.println(strWordEncoded);
}

But I'm getting the following String ( missing the last zero compared to C# string):

QnB6MkdqZzAxZDdWZkdmRDhaUDFVQT09

In my second attempt I used the BouncyCastle Base64 encoder:

public static void main(String[] args) {
   String strWord = "Bpz2Gjg01d7VfGfD8ZP1UA==";
   byte[] encbuff = strWord.getBytes(StandardCharsets.UTF_8);
   String strWordEncoded = new String(Base64.encode(encbuff));
   System.out.println(strWordEncoded);
}

But I'm getting the exact same previous String( still missing the last zero):

QnB6MkdqZzAxZDdWZkdmRDhaUDFVQT09

Does anyone know what may be happening?

I found a solution based on the comments made to me, basically I look at the source code of the method in the Reference Source of Microsoft.

Then I translated the C# code to Java code, and it looks like this:

public static String UrlTokenEncode(byte[] input) {
     try {
         if (input == null) {
         return null;
         }

         if (input.length < 1) {
             return null;
         }

         String base64Str = null;
         int endPos = 0;
         char[] base64Chars = null;

         base64Str = Base64.toBase64String(input);
         if (base64Str == null) {
             return null;
         }

         for (endPos = base64Str.length(); endPos > 0; endPos--) {
             if (base64Str.charAt(endPos - 1) != '=') {
                 break;
             }
         }

         base64Chars = new char[endPos + 1];
         base64Chars[endPos] = (char) ((int) '0' + base64Str.length() - endPos);
         for (int iter = 0; iter < endPos; iter++) {
             char c = base64Str.charAt(iter);
              switch (c) {
                 case '+':
                     base64Chars[iter] = '-';
                     break;
                 case '/':
                     base64Chars[iter] = '_';
                     break;
                 case '=':
                     base64Chars[iter] = c;
                 break;
                 default:
                     base64Chars[iter] = c;
                 break;
             }
          }
         return new String(base64Chars);
     } catch (Exception e) {
         return null;
     }
}

Finally I tested the method and I got the desire output:

public static void main(String[] args) {
   String strWord = "Bpz2Gjg01d7VfGfD8ZP1UA==";
   byte[] encbuff = strWord.getBytes(StandardCharsets.UTF_8);
   String strWordEncoded = UrlTokenEncode(encbuff);
}

M2NIclh4eEwxRGp2MEsyeFc0SHVDZz090