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Question 6 :

What is externalization? Where is it useful?

Answer :

Use the Externalizable interface when you need complete control over your Bean's serialization (for example, when writing and reading a specific file format).

Question 7 :

What is a marker interface ?

Answer :

An interface that contains no methods. E.g.: Serializable, Cloneable, SingleThreadModel etc. It is used to just mark java classes that support certain capability.

Question 8 :

What are tag interfaces?

Answer :

Tag interface is an alternate name for marker interface.

Question 9 :

What are the restrictions placed on static method ?

Answer :

We cannot override static methods. We cannot access any object variables inside static method. Also the this reference also not available in static methods.

Question 10 :

What is JVM?

Answer :

JVM stands for Java Virtual Machine. It is the run time for java programs. All are java programs are running inside this JVM only. It converts java byte code to OS specific commands. In addition to governing the execution of an application's byte codes, the virtual machine handles related tasks such as managing the system's memory, providing security against malicious code, and managing multiple threads of program execution.