Synchronized means only one thread can modify a hash table at one point of time. Any thread before performing an update on a hashtable will have to acquire a lock on the object while others will wait for lock to be released
In the context of Hashtable in Java, the synchronized keyword is used to indicate that the methods of the Hashtable are synchronized. Synchronization in this context means that the Hashtable is thread-safe, and multiple threads can safely access and modify it concurrently without causing data corruption or inconsistencies.
When a method is marked as synchronized in the context of Hashtable, it means that only one thread can execute that method at a time. This ensures that the internal state of the Hashtable is not corrupted due to concurrent access.
For example, if you have a Hashtable object and you want to ensure that multiple threads can safely access and modify it, you might use synchronized methods or blocks to achieve thread safety:
Hashtable<Object, Object> synchronizedHashtable = new Hashtable<>();
// Synchronized method
synchronized(synchronizedHashtable) {
synchronizedHashtable.put(key, value);
}
// or
// Synchronized method
public synchronized void modifyHashtable(Object key, Object value) {
synchronizedHashtable.put(key, value);
}
By using synchronization, you avoid potential race conditions and ensure that the Hashtable operations are atomic with respect to each other.