What are the main advantages and disadvantages of using the synchronized keyword in Java?

The synchronized keyword in Java is used to ensure thread safety by blocking access to critical sections of code so that only one thread can execute them at a time.

Advantages:

• Easy to use for protecting shared resources.
• Guarantees atomicity and visibility of changes between threads.
• Helps prevent race conditions and other multithreading issues.

Disadvantages:

• Can lead to reduced performance due to locking.
• Possibility of deadlocks if synchronization is improperly organized.
• Limits parallelism as threads wait for the monitor to be released.

Example of usage:

public class Counter {
    private int count = 0;

    public synchronized void increment() {
        count++;
    }

    public synchronized int getCount() {
        return count;
    }
}

In this example, the increment and getCount methods are synchronized to prevent multiple threads from modifying the count variable simultaneously.