java - BufferedReader with FileReader use alot of RAM -

i use bufferedreader , filereader on big files (~100g)

bufferedreader reader = new bufferedreader(new filereader("file path")); bufferedwriter writer = new bufferedwriter(new filewriter("output file")); string line; while ((line = reader.readline()) != null) {     // check if need line, , if need it, print     writer.write(line);     writer.newline(); } writer.close(); reader.close(); 

when run source on files, in beginning use low memory, used memory grows(can use on 50g of ram).

why it's that? , can fix it?

i see when run java program on linux command line -xmx parameter, reason make java program need alot of ram.

from when remove -xmx parameter, java program use low memory.

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this old command:

java -xmx350g -jar myjar.jar 

this new command:

java -jar myjar.jar