like what is the logic is
#could you explain what this code is doing in terms of implementing the problem in the picture?
halcyon hull
unborn quailBOT
<@&987246399047479336> please have a look, thanks.
halcyon hull
private int count = 0;
public int getCount() {
return count;
}
public void increment() {
count++;
}
//The synchronized keyword makes this method thread-safe.
public synchronized void synchronizedIncrement() {
count++;
}
public void brokenIncrement() {
int temp = count; // Read
count = temp + 1; // Write
}
public void betterIncrement() {
count++;
}
} ```
public static void main(String[] args) throws InterruptedException {
int numThreads = 1000;
int numIncrements = 1000;
// Example 1: Demonstrating the race condition with brokenIncrement()
Counter counter1 = new Counter();
Thread[] threads1 = new Thread[numThreads];
for (int i = 0; i < numThreads; i++) {
threads1[i] = new Thread(() -> {
for (int j = 0; j < numIncrements; j++) {
counter1.brokenIncrement();
}
});
threads1[i].start();
}
for (Thread thread : threads1) {
thread.join(); // Wait for all threads to finish
}
System.out.println("Race Condition Example (brokenIncrement): Expected: " + (numThreads * numIncrements) + ", Actual: " + counter1.getCount());```
Counter counter2 = new Counter();
Thread[] threads2 = new Thread[numThreads];
for (int i = 0; i < numThreads; i++) {
threads2[i] = new Thread(() -> {
for (int j = 0; j < numIncrements; j++) {
counter2.synchronizedIncrement();
}
});
threads2[i].start();
}
for (Thread thread : threads2) {
thread.join();
}
System.out.println("Synchronized Example: Expected: " + (numThreads * numIncrements) + ", Actual: " + counter2.getCount());
// Example 3: Showing a correct implementation with betterIncrement() (atomic)
Counter counter3 = new Counter();
Thread[] threads3 = new Thread[numThreads];
for (int i = 0; i < numThreads; i++) {
threads3[i] = new Thread(() -> {
for (int j = 0; j < numIncrements; j++) {
counter3.betterIncrement();
}
});
threads3[i].start();
}
for (Thread thread : threads3) {
thread.join();
}
System.out.println("Atomic Example: Expected: " + (numThreads * numIncrements) + ", Actual: " + counter3.getCount());
}
}```^thats all one code, discord was saying it is too long to be in one block]
shy perch
like what is the logic is
it is trying to illustrate what happens when you access a variable concurrently from multiple threads, assuming the objective is to increment private int count = 0; 1000000 times
the 1st example launches 1000 threads and just lets all of them call brokenIncrement() at once, which results in a race condition because 2 threads might read the same variable at the same time and overwrite each other's attempted increment like t1: read t2: read t1: increment and write t2: increment and write so you egt something like 997908 increments instead of 100K every single time
2nd example makes the code meet the objective by wrapping the increment in a synchronized block
3rd example doesn't seem complete but it's hinting at using java.util.concurrent.atomic.AtomicInteger https://www.baeldung.com/java-atomic-variables with thread-safe methods like incrementAndGet()
