Telephonic Interview with Ariba Bangalore.

One of my friend recently attended a telephonic interview with Ariba technologies. These are the info that he shared with me

The interview started with the objective to know the skill of the candidate in core java. The interviewer described about the team that is recruiting. This candidate is responsible for the development of the new feature in the Ariba buyer team.

The questions were

1. Details of the latest project that you are involved ?

This was followed with core java question.

2. Difference between == operator and Equals method ?

== is used to check the equality of the reference of the object while the equals method inherited from the Object class does the same. But this method can be overridden to check of two objects were meaningfully equivalent. say

Person a = new Person(1);

Person b = new Person(1);

Person c = a;

Person takes a int to set the Id of the Person which is compared in the overridden method of the Person.

In this case, the == test will return true for Person a and c while equal comparison will return true for Person a, b and c too.

3. What is the difference between abstract and interface in terms of design ?

Abstract class is a class which has one or more abstract methods and can have other concrete methods that can be shared with the sub classes. While interface is a strict abstract class where all the methods are abstract. (This ans was considered bookish and was asked to give ans in terms of design). Extending abstract class makes the sub class of that type, while the implementation of the interface means the class can be of other type too.

4. What happens when you run a Java program?

Needs to explain the internals of JVM in this case. Please refer to the post on JVM

5. What is method area in Java ?

Method area is a runtime data area in the JVM. Once the class loader has successfully loaded the class, the information regarding the class type are stored in the Method area. Refer to the JVM Post for more details.

6. what is pattern and explain any pattern ?

A pattern is a solution for the common design problem encountered by the developer. For example, Decorator Pattern is used to add the behaviour of to the existing class. This gives the flexibility to the add behaviour without changing the code. Example is java.io package, where FileWriter and FileReader are decorated with BufferedReader and BufferedWriter to add the high level access control to the files.

The telephonic interview went for 30 mins. Will update the post if I get any more details about the personal interview.