API for simple File (line count) functions in Java

Question

Hi : Given an arbitrary file (java), I want to count the lines.

This is easy enough, for example, using Apache's FileUtils.readLines(...) method...

However, for large files, reading a whole file in place is ludicrous (i.e. just to count lines).

One home-grown option : Create BufferedReader or use the FileUtils.lineIterator function, and count the lines.

However, I'm assuming there could be a (low memory), up to date API for doing simple large File operations with a minimal amount of boiler plate for java --- Does any such library or functionality exist anywhere in the any of the Google, Apache, etc... open-source Java utility libraries ?

Answer 1

Java 8 short way:

 Files.lines(Paths.get(fileName)).count();

But most memory effiecint:

try(InputStream in = new BufferedInputStream(new FileInputStream(name))){
    byte[] buf = new byte[4096 * 16];
    int c;
    int lineCount = 0;
    while ((c = in.read(buf)) > 0) {
       for (int i = 0; i < c; i++) {
           if (buf[i] == '\n') lineCount++;
       }
    }
}

You do not need String objects in this task at all.