Behavior of default FileInputStream?

Hey, Finally, it passes. But I don't know what was wrong. I just tried to compare code with others. And I add a line import on the top. fix “not equals” in line 14. The second argument was with -1 fileName.length()-1 and then I print it gives me ".tx" missing last character. So I removed it and now is correct ".txt" 4 characters. Assign substring result to variable. Remove line 23. And it passes, after a few attempts, and I am confused. 😖 Because this should hit 3rd req. not 2nd.

package pl.codegym.task.task18.task1814;

import java.io.*;
import java.io.FileInputStream;

/*
UnsupportedFileName
*/

public class TxtInputStream extends FileInputStream {

    public TxtInputStream(String fileName) throws UnsupportedFileNameException, IOException {
        super(fileName);

        String subFileName = fileName.substring((fileName.length()-4), (fileName.length()));

        if ( !subFileName.equals(".txt")) {
            super.close();
            throw new UnsupportedFileNameException();
        }
    }

    public static void main(String[] args) throws IOException, UnsupportedFileNameException {

    }
}

I tried to use main method to print some text file to console, but it throws exceptions ex. our UnsupportedFilenameException. But maybe it was caused by wrong 2nd substring argument. Now I don't remember because I tried few times. Like this way: String toConsole = null; TxtInputStrem myStream = new TxtInputStream(myFile); while (myStream.avaiable() > 0) { toConsole = myStream.read(); } myStream.close(); sout(toConsole);

Ahh I check it again. I have opened task 1813 and when I run this task1804 it throws:

C:\Users\PC\Desktop\CodeGym\CodeGymTasks\2.JavaCore\src\pl\codegym\task\task18\task1813\AmigoOutputStream.java:15:9
java: constructor AmigoOutputStream in class pl.codegym.task.task18.task1813.AmigoOutputStream cannot be applied to given types;
  required: no arguments
  found: java.io.FileOutputStream
  reason: actual and formal argument lists differ in length

Or to it work I must complete previous task 1813?

Or to it work I must complete previous task 1813? The Codegym project is one huge project with many main methods. Intellij has the 'feature' to remember the last used main method in such projects. To switch to another main one way is to right click the little green arrow next to the main method (or class) you want to run and select 'Run SomClass.main()'

OK outstanding tasks1813 completed, and I run this code again, and I think works, throwing numbers. When I switch "file.txt" to "file.bmb" gives me exception. UnsupportedFilenameException.

String toConsole = null;
        TxtInputStream myStream = new TxtInputStream("C:\\Users\\PC\\Desktop\\CodeGym\\CodeGymTasks\\2.JavaCore\\src\\pl\\codegym\\task\\task18\\task1810\\file.txt");
        while (myStream.available() > 0) {
            toConsole += myStream.read();
        }
        myStream.close();
        System.out.println(toConsole);

Finally, it passes. But I don't know what was wrong. I just tried to compare code with others. And I add a line import on the top. That was not an issue. You already imported

import java.io.*;

And the asterix means that you want to import all classes inside the package java.io. That includes of course FileInputStream as well. The main issue was to use the super() constructor. As said, FileInputStream has no no-args constructor and hence you can not invoke it. This will not compile. Once you had fixed that problem with calling the super taking a String (meaning FileInputStream(String)), you are able to test your code. At that moment most probably the second requirement failed because your class didn't behave like a FileInputStream when you passed a txt file to it. Instead you threw an exception.

Thanks Thomas👍