A Synchronized block is a piece of code that can be used to perform synchronization on any specific resource of the method. A Synchronized block is used to lock an object for any shared resource and the scope of a synchronized block is smaller than the synchronized method.
Syntax
synchronized(object) {
// block of code
}Here, an object is a reference to the object being synchronized. A synchronized block ensures that a call to a method that is a member of an object occurs only after the current thread has successfully entered the object’s monitor.
Example
class TicketCounter {
int availableSeats = 2;
void bookTicket(String name, int numberOfSeats) {
if((availableSeats >= numberOfSeats) && (numberOfSeats > 0)) {
System.out.println(name+" : "+ numberOfSeats + " Seats Booking Success");
availableSeats -= numberOfSeats;
} else {
System.out.println(name +" : Seats Not Available");
}
}
}
class TicketBookingThread extends Thread {
TicketCounter tc;
String name;
int seats;
TicketBookingThread(TicketCounter tc, String name, int seats) {
this.tc = tc;
this.name = name;
this.seats = seats;
}
public void run() {
synchronized(tc) { // synchronized block
tc.bookTicket(name, seats);
}
}
}
public class SynchronizedBlockTest {
public static void main(String[] args) {
TicketCounter tc = new TicketCounter();
TicketBookingThread t1 = new TicketBookingThread(tc, "Adithya", 2);
TicketBookingThread t2 = new TicketBookingThread(tc, "Jai", 2);
t1.start();
t2.start();
}
}Output
Adithya : 2 Seats Booking Success Jai : Seats Not Available