title: Tomcat broken download stream
body: <p>I have a file download servlet running on Tomcat, the code is</p>
  
  <pre><code>public void service(HttpServletRequest request, HttpServletResponse response) throws IOException {
      byte buf[] = new byte[1024 * 4];
      try {
          File file = new File(realFilename);
          int size = (int) file.length();
          BufferedInputStream realFile = new BufferedInputStream(new FileInputStream(file));
          OutputStream out = response.getOutputStream();
          response.setContentLength(size);
          while (true) {
              int count = realFile.read(buf);
              if (count == -1) {
                  break;
              }
              out.write(buf, 0, count);
          }
          out.flush();
      } catch (FileNotFoundException e) {
          logger.error("Stream download failed, file not found: " + realFilename, e);
          response.sendError(404);
      } catch (Exception e) {
          logger.error("DownloadException:", e);
      }
  }
  </code></pre>
  
  <p>However once in a while I get an error that prevents files from being downloaded:</p>
  
  <pre><code>DownloadException:  java.net.SocketException: Broken pipe
          at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:366)
          at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432)
          at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347)
          at org.apache.catalina.connector.OutputBuffer.writeBytes(OutputBuffer.java:392)
          at org.apache.catalina.connector.OutputBuffer.write(OutputBuffer.java:381)
          at org.apache.catalina.connector.CoyoteOutputStream.write(CoyoteOutputStream.java:89)
          at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
          at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:269)
          at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
          at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
          at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
          at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
          at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
          at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
          at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
          at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
          at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
          at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
          at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
          at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
          at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:113)
          at java.lang.Thread.run(Thread.java:619)
  Caused by: java.net.SocketException: Broken pipe
          at java.net.SocketOutputStream.socketWrite0(Native Method)
          at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:92)
          at java.net.SocketOutputStream.write(SocketOutputStream.java:136)
          at org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:750)
          at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:432)
          at org.apache.tomcat.util.buf.ByteChunk.append(ByteChunk.java:347)
          at org.apache.coyote.http11.InternalOutputBuffer$OutputStreamOutputBuffer.doWrite(InternalOutputBuffer.java:773)
          at org.apache.coyote.http11.filters.IdentityOutputFilter.doWrite(IdentityOutputFilter.java:118)
          at org.apache.coyote.http11.InternalOutputBuffer.doWrite(InternalOutputBuffer.java:583)
          at org.apache.coyote.Response.doWrite(Response.java:560)
          at org.apache.catalina.connector.OutputBuffer.realWriteBytes(OutputBuffer.java:361)
          ... 23 more
  </code></pre>
  
  <p>How can I prevent such an error?</p>