Under what conditions does Java's Scanner.hasNextLine() block?

Question

The javadoc for Scanner.hasNextLine() states:

Returns true if there is another line in the input of this scanner. This method m

Answer 1

It depends on the source that the Scanner gets the input from.

For example, if it's a file, the entire input is available, so hasNextLine() wouldn't block (since it can know with certainty when the end of the file is reached and there's no more input.

On the other hand, if the source is standard input, there can always be more input - the user can always type more input - so hasNextLine() would block until the user types in a new line of input.