Java NIO SocketChannel writing problem

Question

I am using Java NIO's SocketChannel to write : int n = socketChannel.write(byteBuffer); Most of the times the data is sent in one or two parts; i.e. if the data could not be sent in one attemmpt, remaining data is retried.

The issue here is, sometimes, the data is not being sent completely in one attempt, rest of the data when tried to send multiple times, it occurs that even after trying several times, not a single character is being written to channel, finally after some time the remaning data is sent. This data may not be large, could be approx 2000 characters.

What could be the cause of such behaviour? Could external factors such as RAM, OS, etc cause the hindarance?

Please help me solve this issue. If any other information is required please let me know. Thanks

EDIT:

Is there a way in NIO SocketChannel, to check, if the channel could be provided with data to write before actual writing. The intention here is, after attempting to write complete data, if some data hasn't been written on channel, before writing the remaining data can we check if the SocketChannel can take any more data; so instead of attempting multiple times fruitlessly, the thread responsible for writing this data could wait or do something else.

Answer 1

TCP/IP is a streaming protocol. There is no guarantee anywhere at any level that the data you send won't be broken up into single-byte segments, or anything in between that and a single segment as you wrote it.

Your expectations are misplaced.

Re your EDIT, write() will return zero when the socket send buffer fills. When you get that, register the channel for OP_WRITE and stop the write loop. When you get OP_WRITE, deregister it (very important) and continue writing. If write() returns zero again, repeat.