string - How can i remove a word/line and replace it with a new one in a txt file (Java)? -

for example have .txt file:

name smth

year 2012

copies 1

and want replace that:

name smth

year 2012

copies 0

using java.io.*.

here code that. let me know if have question.

import java.io.bufferedreader; import java.io.bufferedwriter; import java.io.file; import java.io.fileinputstream; import java.io.fileoutputstream; import java.io.ioexception; import java.io.inputstreamreader; import java.io.outputstreamwriter; import java.io.writer; import java.util.linkedhashmap; import java.util.map;  public class test2 {     map<string, string> somedatastructure = new linkedhashmap<string, string>();     file filedir = new file("c:\\temp\\test.txt");      public static void main(string[] args) {         test2 test = new test2();         try {             test.readfileintoadatastructure();             test.writefilefromadatastructure();         } catch (ioexception e) {             system.out.println(e.getmessage());         }     }      private void readfileintoadatastructure() throws ioexception {         bufferedreader in = new bufferedreader(new inputstreamreader(                 new fileinputstream(filedir)));         string line;         while ((line = in.readline()) != null) {             if (line != null && !line.trim().isempty()) {                 string[] keyvalue = line.split(" ");                 // own index , null checks here sample                 somedatastructure.put(keyvalue[0], keyvalue[1]);             }         }         in.close();     }      private void writefilefromadatastructure() throws ioexception {         writer out = new bufferedwriter(new outputstreamwriter(                 new fileoutputstream(filedir)));         (string key : somedatastructure.keyset()) {             // apply whatever business logic want apply here             mybusinessmethod(key);             out.write(key + " " + somedatastructure.get(key) + "\n");             out.append("\r\n");             out.append("\r\n");         }         out.flush();         out.close();     }      private string mybusinessmethod(string data) {         if (data.equalsignorecase("copies")) {             somedatastructure.put(data, "0");         }         return data;     } }