סנכרון
מישהו יכול להסביר לי מה הבעיה שהוא מדבר עליה?
The most common concurrency problem I've seen, is not realizing that a field written by one thread is not guaranteed to be seen by a different thread. A common application of this:
class MyThread extends Thread {
private boolean stop = false;
public void run() {
while(!stop) {
doSomeWork();
}
}
public void setStop() {
this.stop = true;
}
}
As long as stop is not volatile or setStop and run are not synchronized this is not guaranteed to work. This mistake is especially devilish as in 99.999% it won't matter in practice as the reader thread will eventually see the change - but we don't know how soon he saw it.
מישהו יכול להסביר לי מה הבעיה שהוא מדבר עליה?
The most common concurrency problem I've seen, is not realizing that a field written by one thread is not guaranteed to be seen by a different thread. A common application of this:
class MyThread extends Thread {
private boolean stop = false;
public void run() {
while(!stop) {
doSomeWork();
}
}
public void setStop() {
this.stop = true;
}
}
As long as stop is not volatile or setStop and run are not synchronized this is not guaranteed to work. This mistake is especially devilish as in 99.999% it won't matter in practice as the reader thread will eventually see the change - but we don't know how soon he saw it.
