Assume three threads share a BankAccount object with balance of zero (0), a ReentrantLock named myLock, and has a condition object on myLock named lowBalanceCondition, as shown below. Thread one calls withdraw(30), then thread two calls withdraw(20)and thread three calls deposit(45). If the starting balance is 0, what is the balance after the three calls and after the waiting threads have had a chance to run? public void deposit(int dollars)
{
MyLock.lock();
Int newBalance = balance + dollars;
System.out.println("depositing");
Balance = newBalance;
LowBalanceCondition.signalAll();
MyLock.unlock();
}
Public void withdraw(int dollars)
{
MyLock.lock();
While (balance

Question

Assume three threads share a BankAccount object with balance of zero (0), a ReentrantLock named myLock, and has a condition object on myLock named lowBalanceCondition, as shown below. Thread one calls withdraw(30), then thread two calls withdraw(20)and thread three calls deposit(45). If the starting balance is 0, what is the balance after the three calls and after the waiting threads have had a chance to run? public void deposit(int dollars)
{
MyLock.lock();
Int newBalance = balance + dollars;
System.out.println("depositing");
Balance = newBalance;
LowBalanceCondition.signalAll();
MyLock.unlock();
}
Public void withdraw(int dollars)
{
MyLock.lock();
While (balance < dollars)
{
LowBalanceCondition.await();
}
Int newBalance = balance - dollars;
System.out.println("withdrawing");
Balance = newBalance;
MyLock.unlock();
}
A) 0
B) 15 or 25
C) 45
D) -5

Quizplus · Accepted Answer

The deposit of 45 will allow both withdraw operations to proceed, resulting in a final balance of 45 - 30 - 20 = -5. However, since the balance cannot be negative, the correct balance after all operations is 0, but the question asks for the balance after the waiting threads have run, which would be 15 or 25 depending on the order of execution.

Assume Three Threads Share a BankAccount Object with Balance of Zero