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Question 6 :

Describe synchronization in respect to multithreading.

Answer :

With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchonization, it is possible for one thread to modify a shared variable while another thread is in the process of using or updating same shared variable. This usually leads to significant errors.


Question 7 :

Explain different way of using thread?

Answer :

The thread could be implemented by using runnable interface or by inheriting from the Thread class. The former is more advantageous, 'cause when you are going for multiple inheritance..the only interface can help.


Question 8 :

What are pass by reference and passby value?

Answer :

Pass By Reference means the passing the address itself rather than passing the value. Passby Value means passing a copy of the value to be passed.


Question 9 :

What is HashMap and Map?

Answer :

Map is Interface and Hashmap is class that implements that.


Question 10 :

Difference between HashMap and HashTable?

Answer :

The HashMap class is roughly equivalent to Hashtable, except that it is unsynchronized and permits nulls. (HashMap allows null values as key and value whereas Hashtable doesnt allow). HashMap does not guarantee that the order of the map will remain constant over time. HashMap is unsynchronized and Hashtable is synchronized.