This commit is contained in:
2026-06-09 18:19:57 +03:30
parent a43eac79a4
commit 8bb261ba35
4 changed files with 49 additions and 22 deletions
@@ -20,18 +20,19 @@ public class DeadlockPreventionWorkshop {
}
public static void useResources(Resource r1, Resource r2) {
// TODO: Prevent deadlock by enforcing a consistent lock acquisition order
// Hint: Compare resource IDs and always synchronize on the resource with the smaller ID first.
System.out.println(Thread.currentThread().getName() + " is attempting to lock " + r1.getName());
synchronized (r1) {
System.out.println("+ " + Thread.currentThread().getName() + " locked " + r1.getName());
Resource first = r1.getId() < r2.getId() ? r1 : r2;
Resource second = r1.getId() < r2.getId() ? r2 : r1;
System.out.println(Thread.currentThread().getName() + " is attempting to lock " + first.getName());
synchronized (first) {
System.out.println("+ " + Thread.currentThread().getName() + " locked " + first.getName());
try { Thread.sleep(100); } catch (InterruptedException ignored) {}
System.out.println(Thread.currentThread().getName() + " is attempting to lock " + r2.getName());
synchronized (r2) {
System.out.println("+ " + Thread.currentThread().getName() + " locked " + r2.getName());
System.out.println(Thread.currentThread().getName() + " using " + r1.getName() + " and " + r2.getName());
System.out.println(Thread.currentThread().getName() + " is attempting to lock " + second.getName());
synchronized (second) {
System.out.println("+ " + Thread.currentThread().getName() + " locked " + second.getName());
System.out.println(Thread.currentThread().getName() + " using " + first.getName() + " and " + second.getName());
}
}
}
@@ -6,15 +6,20 @@ import java.util.concurrent.locks.ReentrantLock;
public class LockWorkshop {
public static int counter = 0;
// TODO: Create a ReentrantLock instance to protect the critical section
private static Lock myLock = new ReentrantLock();
public static class MyRunnable implements Runnable {
@Override
public void run() {
int i;
for (i = 0; i < 1_000_000; i++) {
// TODO: Acquire the lock, increment the counter, and release the lock safely in a finally block
myLock.lock();
try{
counter += 1;
}finally {
myLock.unlock();
}
}
System.out.println("Increments completed by " + Thread.currentThread().getName() + ": " + i);
}
@@ -1,18 +1,23 @@
package workshop.exercises;
import static java.lang.Thread.sleep;
public class SynchronizedWorkshop {
public static int counter = 0;
// TODO: Define a lock object to prevent race condition
private static Object lock = new Object();
public static class MyRunnable implements Runnable {
@Override
public void run() {
int i;
for (i = 0; i < 1_000_000; i++) {
// TODO: Use a synchronized block to protect the counter increment
counter += 1;
synchronized (lock){
counter++;
}
}
System.out.println("Increments completed by " + Thread.currentThread().getName() + ": " + i);
}
}
@@ -19,28 +19,44 @@ public class TaylorSeries {
this.n = n;
}
@Override
public void run() {
// TODO: Calculate the n-th term of the Taylor series for sin(x):
// term = (-1)^n * (x^(2n+1)) / (2n+1)!
// Add the term to the global sum ensuring thread-safety.
BigDecimal numarator = x.pow((2*n)+1 , mc);
BigDecimal demenator = factorial(2*n+1);
BigDecimal totalvalue = numarator.divide(demenator , mc);
if(n%2 == 1){
totalvalue = totalvalue.negate();
}
synchronized (sumlock){
sum = sum.add(totalvalue);
}
}
// TODO: Implement factorial(k) using BigDecimal
private BigDecimal factorial(int k) {
return BigDecimal.ZERO;
BigDecimal result = BigDecimal.ONE;
for(int i = 1 ; i <= k ; i++){
result = result.multiply(BigDecimal.valueOf(i) , mc);
}
return result;
}
}
public static BigDecimal sum = BigDecimal.ZERO;
private static Object sumlock = new Object();
public static void main(String[] args) {
ExecutorService threadPool = Executors.newFixedThreadPool(4);
sum = BigDecimal.ZERO;
BigDecimal x = new BigDecimal("0.01");
// Submit tasks to calculate terms
for (int i = 0; i < 100; i++) {
threadPool.execute(new CalculateSin(x , i));
// TODO: Submit task to the thread pool
}