Java Interview Questions and Answers for Experienced Professionals - 1

Question: 1

What is the difference between synchronized and synchronized block?

In case of synchronized method a thread may need to have the lock for a longer time as compared to the synchronized block.

Another difference between the synchronized method and block is that we don’t specify the particular object whose monitor is required to be obtained by thread for entering a synchronized method, whereas we can specify the particular object in case of synchronized block.

Question: 2

What is transient variable?

A transient variable is a variable that may not be serialized during serialization and which is initialized by its default value during de serialization.

Question: 3

What is synchronization?

The Synchronization is the mechanism that ensures that only one thread is accessed the resources at a time.

 With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources.

Without synchronization, it is possible for one thread to modify a shared object while another thread is in the process of using or updating that object’s value.

This often causes dirty data and leads to significant errors.

Question: 4

What is deadlock?

When two threads are waiting each other and can’t precede the program is said to be deadlock.

Question: 5

How can a dead thread be restarted?

A dead thread cannot be restarted.