Why is BufferedReader read() much slower than readLine()?

Question

I need to read a file one character at a time and I\'m using the read() method from BufferedReader. *

I found that read() is a

Answer 1

According to the documentation:

Every read() method call makes an expensive system call.

Every readLine() method call still makes an expensive system call, however, for more bytes at once, so there are fewer calls.

Similar situation happens when we make database update command for each record we want to update, versus a batch update, where we make one call for all the records.