java - How to count position of empty row? -

i've got flat file this:

[doc] date=14.01.15 symbol=muka [content] [pos1] name=muka2,0 0,9l ml  [doc] date=14.01.15 symbol=muka [content]  [doc] date=14.01.15 symbol=muka [content] [pos1] name=muka2,0 0,9l ml 

i want delete [doc] statement content empty. i'm trying checking line have string "[content]" , next line empty. want number of line (number of row line empty after "[content]") , add list. [doc] empty [content] part have 4 lines. when [content] position can substract 4 , delete lines between position , position -4.

the file after execution have this:

[doc] date=14.01.15 symbol=muka [content] [pos1] name=muka2,0 0,9l ml  [doc] date=14.01.15 symbol=muka [content] [pos1] name=muka2,0 0,9l ml 

i'm trying function:

public void countdesiredlines() throws ioexception {     bufferedreader reader = new bufferedreader(new filereader(             "d:\\temp.txt"));      int lines = 0;      boolean zawiera = false;     while (reader.readline() != null) {         lines++;         string line = reader.readline();         if (zawiera == true) {             zawiera = false;             if ("".equals(line)) {                 pozycje.add(lines);              }         }         if (line.startswith("[content]")) {             zawiera = true;          }          reader.close();          system.out.println("wartość pod: " + pozycje.size());         // (int = 0; < pozycje.size(); i++) {         // system.out.println("wartość pod: "+ pozycje.get(i).tostring());         // }     } } 

i've got errors like:

wartość pod: 0 java.io.ioexception: stream closed @ java.io.bufferedreader.ensureopen(bufferedreader.java:115) @ java.io.bufferedreader.readline(bufferedreader.java:310) @ java.io.bufferedreader.readline(bufferedreader.java:382) @ textformatter.countdesiredlines(textformatter.java:190) @ textformatter.main(textformatter.java:51) 

i'm new in java. if have clues or advices please let me know. time.

you calling readline() twice each iteration, read past end of file. change:

while (reader.readline() != null) {     lines++;     string line = reader.readline(); 

to

string line = null; while ((line = reader.readline()) != null) {     lines++; 

also, calling reader.close() inside loop. have move outside loop logic work.