How to read a single line from file in java

Question

How can i read single line from a text file in java. and what is the criteria of knowing that line is completed.

secondly

i read file and then for Read Line

Answer 1

First thing : readLine() returns String value only so it is not converting to String.

Second thing : In your while loop, you read firstline and check whether the content of first line is null or not. But when data = infile.readLine(); executes, it will fetch second line from file and print it to Console.

Change your while loop to this :

while((data = infile.readLine()) != null){ 
    System.out.println(data); 
}

If you use toString() method, it will throw NPE when it will try to use toString method with null content read from infile.