android - Read and Write to file in the same time -

i want write , read file in same time without errors. example, starting new thread writing file running service. in activity starting new thread reading same file. wan't synchronously. thing :

1. to wait execution of next thread until previous finished.
2. next thread must not start until previous thread stops, irrespective of time consumption.

my code read , write:

public static final string route_file_name = "route.txt";      public static void savepointtofile(context context, string point) throws ioexception {          fileoutputstream fout = context.openfileoutput(route_file_name, context.mode_append);          outputstreamwriter osw = new outputstreamwriter(fout);         osw.write(point);         osw.flush();         osw.close();     }      public static string readroutefromfile(context context) {         stringbuffer filecontent = new stringbuffer(uiutils.emptystring());         byte[] buffer = new byte[1024];         try {             fileinputstream fis = context.openfileinput(route_file_name);              int length;              while ((length = fis.read(buffer)) != -1) {                 filecontent.append(new string(buffer));             }          } catch (filenotfoundexception e) {             e.printstacktrace();         } catch (ioexception e) {             e.printstacktrace();         }         return filecontent.tostring();     } 

thanks in advance.

if want read method called thread wait write method called thread finished, , vice versa, synchronize both methods on common object:

private static final object filelock = new object();  public static string readfile() {     synchronize(filelock) {         [your current read code here]     }  }  public static void write(string data) {     synchronize(filelock) {         [your current write code here]     }  }