Author(s)
When we are working with Threads, it’s important to know when to use a daemon or a non-daemon Thread.
Do you know if the main Thread is a daemon or not? And do you know what a daemon Thread is?
That’s what you will find out by trying out the following Java Challenge!
It's time to improve your Java skills with this Daemon Thread Challenge...
Daemon Thread Challenge
What will happen when running the following main method?
public class DaemonThreadChallenge implements Runnable {
public static void main(String... doYourBest) {
Thread thread = new Thread(new DaemonThreadChallenge());
thread.setDaemon(true);
thread.start();
}
@Override
public void run() {
for (;;) {
System.out.println("For ever");
}
}
}
A) It will print "Forever" for an indeterminate time and the program will finish normally.
B) It will throw StackOverflowError because of the infinite looping.
C) It will print "Forever" infinitely.
Explanation:
The amount of time that "Forever" will be printed is indeterminate because it will depend on the time from the main thread execution.
There are two types of threads:
- Non-daemon: the main method is executed with a non-daemon thread behind the scenes and this thread will be executed until the end.
- Daemon: it will die if all non-daemon threads have finished. So in this quiz, if the main method is finished, the daemon thread we created will be finished as well because all daemon threads depend on a non-daemon thread to continue its execution.
Therefore, the final answer will be... what do you think?
That's it challenger, keep pushing your limits to be a better software developer!
-
Java Thread Programming (Part 1)
We write code in a file line by line, and then it gets executed. To be able to execute a piece of code requires an execution environment. In Java, a thread is an executing environment. If a program has only one executing environment, then we call this program a single-threaded program.
Read More
-
8 Debugging Tips for IntelliJ IDEA Users You Never Knew Existed
As developers, we’re all familiar with debuggers. We use debugging tools on a daily basis – they’re an essential part of programming. But let’s be honest. Usually, we only use the breakpoint option. If we’re feeling frisky, we might use a conditional breakpoint.
But guess what, the IntelliJ IDEA debugger has many powerful and cutting-edge features that are useful for debugging more easily and efficiently.
Read More
-
A Closer Look at JFR Streaming
Since JDK 14, there is a new kid on the block – Java Flight Recorder streaming, which enables developers to subscribe to JFR data.
It is a feature allowing a developer to subscribe to select JFR data and to decide what to do with that data in the host process. JFR events can also be consumed from a separate process by pointing to the file repo of a separate JVM process – the mechanism is the same.
Read More