Unable to execute Java code in SciTE

Question

I have written a sample code:

import java.util.Scanner;

 public class abcd {
    public static void main(String[] args) {
        System.out.print("please enter a: ");
        Scanner a = new Scanner(System.in);
        String b = a.next();
        System.out.println(b);
    }
}

I am able to compile and execute this code via Ubuntu terminal. In SciTe, it compiles fine, but when I run it, I am faced with this error:

please enter a: Exception in thread "main" java.util.NoSuchElementException
    at java.util.Scanner.throwFor(Scanner.java:862)
    at java.util.Scanner.next(Scanner.java:1371)
    at abcd.main(abcd.java:8)

Any Suggestions?

EDIT: When I execute a file in terminal, I do: 'java abcd' Scite does: 'java -cp .abcd'. How are the two commands different and why isn't java -cp working?

Answer 1

It appears that there is a bug/improper implementation in the handling of standard input in SciTE on Linux/Unix.

The description of the bug and a workaround are in this PDF document: A Problem with SciTE Go Command on Linux

Note: this is not official documentation, but it seems to match your problem.

According to that document, when running a Java program through the "Go" command on SciTE, input is supposed to come from the output pane. However, on Linux this does not work properly, and it's as if you are reading from an empty stream.

When you are reading from an empty stream, Scanner sees the end-of-file marker when it attempts to read a value using next(), nextInt() etc. And it throws a NoSuchElementException as there is no input element in the stream.

Your options to work around this problem:

• Try the method mentioned in the aforesaid document, to use "Go" in a Linux terminal instead of the output pane.
• Run the program in a terminal and avoud the "Go" command altogether.
• Use a different IDE which doesn't have this problem.

Answer 2

Try to use hasNext() before next();

import java.util.Scanner;
public class abcd {
  public static void main(String[] args) {
    System.out.print("please enter a: ");
    Scanner a = new Scanner(System.in);
    while(a.hasNext()) {
      try {
        String b = a.next();
        System.out.println(b);
      } catch (NoSuchElementException e) {}
    }
  }
}

Answer 3

I don't mean to offend, but using hasNext() as suggested in Alexander's answer won't solve this problem, it will only enable OP to handle it well. I don't think that is what he/she is looking for.

Now I am no expert by any means and for some reason your program code works on my machine... But anyways, a NoSuchElementException is thrown when your program is cycling over an iterable object and there is nothing more to cycle over, despite your program expecting something there. A quick look-up in the Java-docs of Scanner.next() shows that this exception is thrown if there are no more tokens available for read.

Now, if I had to guess I would advise you to try using something other than Scanner.next() and see if that works.

The fact that it works on my machine but not on yours is somewhat surprising, so could you provide some information on how you try to run your program? Are you running it from the default command-line? Or within Scite? (If second is the case, I really won't be able to help you, I have never even touched Scite).