String lineseperator = java.security.AccessController .doPrivileged(new sun.security.action.GetPropertyAction( "line.separator"));

Access restriction: The constructor 'GetPropertyAction(String)' is not API

1. Go to the Build Path settings in the project properties.
2. Remove the JRE System Library
3. Add it back; Select "Add Library" and select the JRE System Library. The default worked for me.

import java.io.File;import java.io.IOException;import java.io.RandomAccessFile;import java.nio.CharBuffer;import java.nio.channels.FileChannel;import java.nio.channels.FileChannel.MapMode;public class memorymapfiledemo {    final static String filepath = "/home/hadoop/test/java.txt";    public static void main(String[] args) throws IOException {        writefile(filepath);        readfile(filepath);    }    static void writefile(String _filepath) throws IOException {        File _file = new File(_filepath);        RandomAccessFile raf = new RandomAccessFile(_file, "rw");        FileChannel fc = raf.getChannel();        int buffersize = 1024 * 8;        CharBuffer cb = fc.map(MapMode.READ_WRITE, 0, buffersize)                .asCharBuffer();        String lineseperator = java.security.AccessController                .doPrivileged(new sun.security.action.GetPropertyAction(                        "line.separator"));        String content = "";        long offset = 0;        for (int i = 1; i <= 1000; i++) {            content = "Line" + i + " hello java" + lineseperator;            if ((cb.limit() - cb.position()) < content.length()) {                offset += cb.position();                cb = fc.map(MapMode.READ_WRITE, offset, buffersize)                        .asCharBuffer();            }            cb.put(content);        }        fc.close();        raf.close();    }    static void readfile(String _filepath) throws IOException {        File _file = new File(_filepath);        RandomAccessFile raf = new RandomAccessFile(_file, "rw");        FileChannel fc = raf.getChannel();        long totalsize = fc.size();        int buffersize = 1024 * 8;        long offset = 0;        CharBuffer cb = fc.map(MapMode.READ_ONLY, 0, buffersize).asCharBuffer();        while (offset < totalsize) {            while (cb.hasRemaining()) {                System.out.print(cb.get());            }            offset += cb.position();            cb = fc.map(MapMode.READ_ONLY, offset, buffersize).asCharBuffer();        }        fc.close();        raf.close();    }}