Suppose I've created an executable jar
from a code where I have used
System.out.println()
When we run the executable jar, there is no console. So, what happens to this line? How does java
handle this situation?
EDIT 01:
NOTE: The situation is when I don't use a console to run the jar
nor associate any console with it anyhow.
EDIT 02: Making things clearer:
I know that nothing will be printed anywhere as there is no console..! I want to know how java
handle this line in this case? Is this line omitted when generating the bytecode for a executable jar? Or is this line just overlooked when there is no console? Or anything...
There's nothing special about running code in an executable jar file. If you run it from a console, e.g. with java -jar foo.jar
the output will still go to the console.
If you run the code in some way that doesn't attach a console - such as javaw
on Windows, which is the default program associated with executable jar files - then the output won't go anywhere. It won't cause any errors - the text will just be lost.
Note that in that case, if you use System.console()
instead, that will return null
. So:
System.out.printf("Foo%n"); // No problem. Goes nowhere.
System.console().printf("Foo%n"); // Would throw a NullPointerException.