Java Scanner & PrintWriter & InputStream & OutputStream

When using both PrintWriter & Scanner, and InputStream & OutputStream on the same socket, odd thing happens.
When call InputStream.read() after call Scanner.nextLong(), InputStream.read() can't receive data exactly. It seems Scanner caches the input.
The solution is send and receive something before call InputStream.read(). Sequence is important like send/receive/send/receive, not like send/send/receive/receive

for client:
    Scanner.nextLong()
    PrintWirter.println()
    InputStream.read()


for server
  PrintWriter.println()
  Scanner.nextLine()
  OutputStream.write()