Problem with "File" constructor

[Emilian Chmiel]

import java.io.*;
public class Stream01
{
public static void main(String[] args) throws IOException {
File inFile = new File ("C:/in.txt");
FileInputStream in = new FileInputStream("C:/in.txt");}
}

Exception in thread "main" java.io.FileNotFoundException: C:\in.txt ...

import java.io.*;
public class Stream02
{
public static void main(String[] args) throws IOException {
File inFile = new File ("C:/in.txt");
inFile.createNewFile();
FileInputStream in = new FileInputStream("C:/in.txt");}
}

Why I must use "inFile.createNewFile();", why constructor dosen't create file ?

[Stephan van Hulst]

It doesn't make sense to create a new file if all you want to do is read it.

File was named poorly. A File does not represent a file on your filesystem. A File represents a path, and the actual file it points to may or may not exist.

You shouldn't use the File class. Instead, use Paths, Path, and Files to open streams and readers:

Path path = Paths.get("C:", "in.txt");
try (
 BufferedReader reader = Files.newBufferedReader(path);
) {
 // Read from text file here.
}

Path path = Paths.get("C:", "out.txt");
try (
 BufferedWriter writer = Files.newBufferedWriter(path, WRITE, CREATE_NEW);
) {
 // Write to text file here.
}

[Carey Brown]

From the Javadocs: An abstract representation of file and directory pathnames.

As such, a File does not know if it refers to an actual storage location until it is asked to perform some operation, e.g. calling exists().

In your example code, creating a file and the opening it up for read doesn't make sense, there's nothing to read immediately after creating it.