Java FileReader vs File

Question

I wanted to create a File/FileReader object to instantiate a Scanner object.

So, the text book had like this:

File file = new File("filename.txt");

However, our instructor was like, that is wrong, the correct way is:

FileReader file = new FileReader("filename.txt");

Both of them work. So, what's the difference between the two and which one's correct.

Answer 1

File(String name)

Creates a new File instance by converting the given pathname string into an abstract pathname. If the given string is the empty string, then the result is the empty abstract pathname.

FileWriter(String name)

Constructs a FileWriter object given a file name.

Basically, the difference is that only Instantiating a File won't allow you to write to it, while FileWriter does.

The constructor of FileWriter pass to OutputStreamWriter a new FileOutputStream which instantiate a File from the given name.

Note that a Scanner is used to read a File not to write in it.

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Edit : To answer to your edited question where you changed FileWriter to FileReader, the main difference between a File and a FileReader is that File does not have a close method while a FileReader does and implement Closeable. Most of the methods offered by File object are meant to manipulate directly the file (check existence, delete, create, list all files from directory). As @Pshemo mentionned, a File is not to be seen as data, but simply as a path.

I recommend to read the File API and FileReader API.