FileOutput Stream delets text file contents

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;

public class FileIoStream {

	public static void main(String[] args) throws IOException {
		File f = new File("C:\\Users\\rs\\IO\\myfile.txt");
		FileInputStream fis = new FileInputStream(f);
		FileOutputStream fos = new FileOutputStream(f);
	}
}

Every time I make an object for FileOutputStream the contents in myfile.txt get deleted and I do not know why?
But when I just new FileInputStream it does not happen.

FileOutputStream by default overwrites the file if it exists. You can use the overloaded constructor to append to that file instead of overwriting it:

FileInputStream fis = new FileInputStream(f, true);
// Here -------------------------------------^

You should try with this constructor :

FileOutputStream fos = new FileOutputStream(f, true);

So what you have to add to the file will be appended if it already exists.

Doc available here

If gets deleted, because it actually gets overwritten. Every time you create a new FileOutputStream object with new FileOutputStream(File file) constructor, a new FileDescriptor is created, and therefore:

> bytes are written to the beginning of the file.

_{You can think of it, like it starts writing to the file by overwriting everything that previously existed in that file.}

You can alternatively create your FileOutputStream object with the FileOutputStream(File f, boolean append) constructor, passing true as a boolean argument into that constructor, and in this case:

> bytes will be written to the end of the file rather than the beginning.

_{You will maintain whatever had been written into the file and your data will be appended to the existing data in the file.}