File Read

try (BufferedReader br = new BufferedReader(new FileReader(file))) {
    String line;
    while ((line = br.readLine()) != null) {
       // process the line.
    }
}

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public static void readText throws FileNotFoundException {
    Scanner scan = new Scanner(new File("samplefilename.txt"));
    while(scan.hasNextLine()){
        String line = scan.nextLine();
        //Here you can manipulate the string the way you want
    }
}

try( BufferedReader reader = new BufferedReader( ... ) ) {
  reader.lines().foreach( line -> processLine( line ) );
}

   String pathFile="/path/to/file.txt";
   String cmd="type";
   if(System.getProperty("os.name")=="Linux"){
       cmd="cat";
   }
   Process p= Runtime.getRuntime().exec(cmd+" "+pathFile);
    BufferedReader stdInput = new BufferedReader(new
         InputStreamReader(p.getInputStream()));
   System.out.println(p.getOutputStream().toString());
   String s = null;
    while ((s = stdInput.readLine()) != null) {
        System.out.println(s);
    }