Why am I getting an EOF Exception?

[fatabass]

I have a file called Human.java and it has 3 three lines of text with 5 characters each.

Here is my code:

public class TestClass {

	public static void main(String[] args) throws IOException {
		BufferedInputStream test = new BufferedInputStream(new FileInputStream(new File("c:/Human.java")));
		System.out.println(test.read());
		System.out.println(test.read());
		DataInputStream den = new DataInputStream(test);
		System.out.println(test.read());
		System.out.println(den.readUTF());
	}
}

And here is the output:

107
111
114
Exception in thread "main" java.io.EOFException
at java.io.DataInputStream.readFully(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at java.io.DataInputStream.readUTF(Unknown Source)
at myPackage.TestClass.main(TestClass.java:19)

What is wrong with my DataInputStream please ?

Thank you.

[JosAH]

Don't read both through the FileInputStream and the DataInputStream; only read through the DataInputStream (it wraps the other stream).

kind regards,

Jos

[fatabass]

Oh so it is like open in both streams thats why ?

[JosAH]

Oh so it is like open in both streams thats why ?

Not really; the wrapped stream is a buffered stream and when you wrap it later (after it has read something already) it may have read ahead and the wrapper stream might only 'see' the last portion of the stream.

kind regards,

Jos

[fatabass]

Interesting.. I would like to learn the reason in detail. Any sources you can suggest ?

[JosAH]

Interesting.. I would like to learn the reason in detail. Any sources you can suggest ?

The API documentation for the entre java.io package will do fine; it shows how all the InputStreams are implemented as 'decorators' or 'wrappers'.

kind regards,

Jos

[fatabass]

When you say the documentation, do you mean: java.io (Java Platform SE 6)

[JosAH]

When you say the documentation, do you mean: java.io (Java Platform SE 6)

Yep, that's the java.io part of the API documentation (for version 1.6); bookmark the entire API documentation, you'll need it.

kind regards,

Jos