Cause of Servlet's 'Response Already Committed' [duplicate]

What are the common possibilities to encounter this exception in servlet - Response Already committed?

The response gets committed because of the following reasons:

• Because the Response buffer has reached the max buffer size. It could be because of the following reasons:

    > the bufferSize in JSP page has reached.You can increase the JSP buffer size 
      in page directive. See here, 
  
     <%@ page buffer="5kb" autoFlush="false" %>
  
    > the server default response max buffer size has reached.You can increase    
      the server default max buffer size.
  
      ServletRespnse.setBufferSize()
  

• Some part of the code has called flushed on the response , i,e, invoked the method HttpServletResponse.flushBuffer().

• Some part of the code has flushed the OutputStream or Writer, i,e, invoked the method HttpServletResponse.getOutputStream().flush() or `HttpServletResponse.getWriter().flush()

• If you have forwarded to another page, where the response is both committed and closed. For example, when response.sendRedirect() has been called, the response is committed.