import java.util.concurrent.Callable; class LineMarkers implements Runnable, Callable, CharSequence{ <caret> public void run() { //To change body of implemented methods use File | Settings | File Templates. } public Object call() throws Exception { return this; } public int length() { return 0; //To change body of implemented methods use File | Settings | File Templates. } public char charAt(int index) { return 0; //To change body of implemented methods use File | Settings | File Templates. } public CharSequence subSequence(int start, int end) { return toString(); } }