Interview Questions

Cloning refers to creating duplicate copies of objects in java.

Shallow Cloning: Shallow cloning is a bitwise copy of an object. New object is created which is an exact copy that of the original one. In case any objects are referring the fields of these objects, just the references are copied.

Deep Cloning: In deep cloning, complete duplicate copy of the original copy is created. Deep cloning creates not only the primitive values of the original objects but also copies all its sub objects as well.

Clonable interface is used to perform cloning in java.

Recovery/error testing is testing how well a system recovers from crashes, hardware failures, or other catastrophic problems.

COMMIT statements are used to release locks which are required for that unit of work, and then permit a new unit of work. In other words, if COMMITS are not coded in the program and the program has been sent for execution, then while processing, in place of just going back to a few inserts since the nearest commit, the program has to go back to the inserts which were made during the entire run of the program. This extra process takes around twice or thrice the time taken normally.

Call center is a subset of BPO. 

A collection just like an array is an ordered group of elements of the same type. Each elements position is determined by a unique subscript.

Index by tables:- They are similar to hash arrays that allows to search for subscript values using arbitrary numbers and strings.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL]

INDEX BY [BINARY_INTEGER | PLS_INTEGER | VARCHAR2(size_limit)];

INDEX BY key_type;

Example:

TYPE studenttyp IS TABLE OF emp%ROWTYPE

INDEX BY BINARY_INTEGER;

stud_tab studenttyp;

Nested tables:- they hold random number of elements and use sequential numbers as sub scripts.

They can be declared as:

TYPE type_name IS TABLE OF element_type [NOT NULL];

Example: TYPE employee_type IS TABLE OF NUMBER INDEX BY VARCHAR2(64);

Varrays: Holds a fixed number of elements which can be changed in run time. 

They can be declared as:

TYPE type_name IS {VARRAY | VARYING ARRAY} (size_limit) OF element_type [NOT NULL];

Example: TYPE Calendar IS VARRAY(366) OF DATE;

- The process of combining data from different resources.

- The combined data is provided to the users with unified view.

- Information from different enterprise domains are integrated – known as Enterprise Information Integration.

- Useful for merging information from different technologies among enterprises.

- The sub areas of data integration are 

1. Data Warehousing.

2. Data Migration.

3. Master Data Management.

Amazon SQS is a message passing mechanism that is used for communication between different connectors that are connected with each other. It also acts as a communicator between various components of Amazon. It keeps all the different functional components together. This functionality helps different components to be loosely coupled, and provide an architecture that is more failure resilient system.

DriverManager is a class in java.sql package. It is the basic service for managing a set of JDBC drivers.