Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly
Appearance settings

fix busy waiting in twin ballthread #3414

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
omrajshinde534 wants to merge 1 commit into
base: master
Choose a base branch
Loading
from
Open

fix busy waiting in twin ballthread #3414

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
42 changes: 24 additions & 18 deletions 42 twin/src/main/java/com/iluwatar/twin/BallThread.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,33 +41,39 @@ public class BallThread extends Thread {
private volatile boolean isRunning = true;

/** Run the thread. */
public void run() {
@Override
public synchronized void run() {

while (isRunning) {
if (!isSuspended) {
twin.draw();
twin.move();
}
try {
Thread.sleep(250);
} catch (InterruptedException e) {
throw new RuntimeException(e);
while (isRunning) {
try {
while (isSuspended) {
wait(); // ❗ block instead of polling
}
twin.draw();
twin.move();
Thread.sleep(250);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
break;
}
}
}


public void suspendMe() {
isSuspended = true;
LOGGER.info("Begin to suspend BallThread");
}
Comment on lines 63 to 66
Copy link
Copy Markdown

@github-actions github-actions Bot Jun 2, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

suspendMe() is currently not synchronized, while run() is. This can create visibility issues for isSuspended updates across threads. Make suspendMe() synchronized (or declare isSuspended as volatile) to ensure the suspension request is observed by the running thread.


public void resumeMe() {
isSuspended = false;
LOGGER.info("Begin to resume BallThread");
}
public synchronized void resumeMe() {
isSuspended = false;
notify(); // ❗ wake up waiting thread
LOGGER.info("Begin to resume BallThread");
}

public void stopMe() {
this.isRunning = false;
this.isSuspended = true;
}
public synchronized void stopMe() {
isRunning = false;
isSuspended = false;
notify(); // ensure thread exits if waiting
}
}
Loading
Morty Proxy This is a proxified and sanitized view of the page, visit original site.