SameProb

public void method1(String filename) {
	BufferedReader br = new BufferedReader(new FileReader(filename));
	int lineNum = 0;
	while (br.readLine() != null) {
		lineNum++;
	}
	br.close();
	br = new BufferedReader(new FileReader(filename));

	int line = (int)(Math.random() * lineNum);
	for (int i = 0; i < lineNum; i++) {
		String l = br.readLine();
		if (i == line) {
			System.out.println(l);
		}
	}
}

public void method1(String filename) {
	BufferedReader br = new BufferedReader(new FileReader(filename));
	final double p = 0.5;
	double q = p;
	
	String line;
	while((line = br.readLine()) != null) {
	  if (Math.random() < q) {
	    System.out.println(line);
	    break;
	  } 
	  q *= (p / (1 - p));
	}
}