Unable to insert properly the text in a already existing file

Question

Hi Everyone,
I am trying to read and write the text file using randomaccess class.
When i am trying to update a line with string its over writing next line with the same number of bytes as my string which i am trying to insert.
For example if my text file has following data
test
most
must
if i try to insert "text" after "test" the program overwriting the "most" word.
if anyone can help that will be great. thanks in advance. Below is the code:
RandomAccessFile raf = new RandomAccessFile(aFile, "rw");
long len1 = raf.length();
long off1 = 0;
String line1;
boolean updated = false;
while ((line1 = raf.readLine()) != null)
int coma;
if ((coma = line1.indexOf(",")) != -1)
String s = line1.substring(0, coma);
if (s.equals(str))
line1.indexOf(",", coma);
StringBuffer nStr = new StringBuffer();
nStr.append(line1);
nStr.append(",");
nStr.append(str1);
nStr.append(System.getProperty("line.separator"));
raf.seek(off1);
raf.writeBytes(nStr.toString());
raf.close();

Answer 1

You can't insert data that way. You are always going to be overwriting data (unless you go past the end of the existing file, in which case you are going to be appending data).
If you want to insert data, here's what you have to do:
1. Write the data before the insertion point to a new file.
2. Write the data you want to insert to that new file.
3. Write the data after the insertion point to a new file.
4. Close the new file.
5. Delete the old file.
6. Rename the new file.