~

src/src/main/java/com/my/graphiteDigesterBg/diframe/util/DiByteBuffer.java

@@ -3,6 +3,10 @@ import java.nio.ByteBuffer;
 public class DiByteBuffer {
     // convert byte buffer to hex string
     public static String toHex ( ByteBuffer buffer ) {
+        if ( null == buffer ) {
+            return "";
+        }
+
         StringBuilder sb = new StringBuilder();
         for (int i = 0; i < buffer.limit(); i++) {
             sb.append(String.format("%02X ", buffer.get(i)));