Java的BufferedReader.readLine（）是否将整个文件放在内存中？

Question

Does it? Or maybe only separate strings are put on each readline() and maximal space of memory taken is volume for the longest string?

Answer 1

Does it?

No.

Or maybe only separate strings are put on each readline()

No.

and maximal space of memory taken is volume for the longest string?

No.

It's a buffered reader. That means it has a buffer. It fills the buffer, to the extent of available data and its own limit, which is or was 4096 characters. It scans the buffer for a line terminator; returns the data before it as the next line; and deletes it from the buffer. When the buffer is empty it fills it again.

What the caller does with each readLine() result is up to the caller.