Using lambda expression to read a csv file

An old fashion way: using BufferedReader

For example, read a csv file, using first column as key and second column as value

Map<String, String> map=new HashMap<>();

BufferedReader br = new BufferedReader(new FileReader(PATH_TO_YOUR_FILE));

String line="";

while((line=br.readLine())!=null){

  String tmp[] = line.split(",");

  map.put(tmp[0],tmp[1]);

  ... THINGS YOU WANT TO DO ... 

}

br.close();

A fancy way: using Stream

Map<String, String> map = Files.lines(Paths.get(PATH_TO_YOUR_FILE))

.map(line -> line.split(","))

.collect(Collectors.toMap( 

      array -> array[0], 

      array -> array[1] 

));