File of 2GB to be handled in Java

Question

I am working with a log file of size 2GB. When heap exceeds max limit, it throws OutOfMemory Error in my log file.

I want to simulate unix command tail -20 native_stdout.log

How do I do this in JAVA?

I cannot read line by line because it has thousands of lines, it is going to take lot of time.

And file I read is streaming one from SFTP serevr.

possibly answered here: [stackoverflow.com/questions/2356137](http://stackoverflow.com/questions/2356137/read-large-files-in-java) — s.ijpma, Jul 09 '15 at 09:19
Actually, answered here - http://stackoverflow.com/questions/4121678/java-read-last-n-lines-of-a-huge-file The simplest and most robust answer is the one that suggests using org.apache.commons.io.input.ReversedLinesFileReader from apache commons.io — pvg, Jul 09 '15 at 09:22
What have you tried and what are you having trouble with? You just need to remember the last 20 lines and once you reach the end, print them out, after that you need to print any additional lines. — Peter Lawrey, Jul 09 '15 at 09:22

score 2 · Answer 1 · edited May 23 '17 at 12:30

2

Apache commons has an Simple implementation of the unix "tail -f" functionality

edited May 23 '17 at 12:30

Community

answered Jul 09 '15 at 09:22

Garry

score 0 · Answer 2 · answered Jul 09 '15 at 09:24

0

You could use BufferedReader.readLine() to read a large file line by line.

answered Jul 09 '15 at 09:24

Andreas Hartmann

That's wildly inefficient for a multi-gig file. – pvg Jul 09 '15 at 09:24
Hi, there are thousands of lines in log file, it is not desirable to read line by line. I need skip all lines but last 10 – Pradeep Kumar S Jul 10 '15 at 11:10

2 Answers2