I/O Interview Questions

Question-125: What is the difference between the Reader/Writer class hierarchy and the InputStream/OutputStream class hierarchy?
Answer:
The Reader/Writer class hierarchy is character-oriented, and the InputStream/OutputStream class hierarchy is byte-oriented.


Question-126: Whatan I/O filter?
Answer:
An I/O filter is an object that reads from one stream and writes to another, usually altering the data in some way as it is passed from one stream to another.


Question-127: What is serialization?
Answer:
Serialization is a process of writing the state of an object into a byte stream.It is mainly used to travel object’s state on the network.


Question-128: What is Deserialization?
Answer:
Deserialization is the process of reconstructing the object from the serialized state.It is the reverse operation of serialization.


Question-129: What is transient keyword?
 Answer:
If you define any data member as transient,it will not be serialized.


Question-130:What is Externalizable?
Answer:
Externalizable interface is used to write the state of an object into a byte stream in compressed format.It is not a marker interface.


Question-131: What is the difference between Serializalble and Externalizable interface?
Answer:
Serializable is a marker interface but Externalizable is not a marker interface.When you use Serializableinterface, your class is serialized automatically by default. But you can override writeObject() and readObject() two methods to control more complex object serailization process. When you use Externalizable interface, you have a complete control over your class’s serialization process.


Question-132: How do I convert a numeric IP address like 192.18.97.39 into a hostname like java.sun.com?
Answer:
By InetAddress.getByName(“192.18.97.39″).getHostName() where 192.18.97.39 is the IP address.


Question-133: What is reflection?
Answer:
Reflection is the process of examining or modifying the runtime behaviour of a class at runtime.It is used in:
IDE (Integreted Development Environment) e.g. Eclipse,MyEclipse,NetBeans. Debugger Test Tools etc.


Question-134: Can you access the private method from outside the class?
Answer:
Yes, by changing the runtime behaviour of a class if the class is not secured.

Collection Interview Questions