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Q:

What are the basic interfaces of Java Collections Framework ?

Answer

Java Collections Framework provides a well designed set of interfaces and classes that support operations on a collections of objects. The most basic interfaces that reside in the Java Collections Framework are:


Collection, which represents a group of objects known as its elements.


Set, which is a collection that cannot contain duplicate elements.


List, which is an ordered collection and can contain duplicate elements.


Map, which is an object that maps keys to values and cannot contain duplicate keys.

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Subject: Java

Q:

What is the difference between processes and threads ?

Answer

- A process is an execution of a program, while a Thread is a single execution sequence within a process.


- A process can contain multiple threads. A Thread is sometimes called a lightweight process.

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Subject: Java

Q:

What is the difference between an Interface and an Abstract class ?

Answer

1.Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior.


2.Variables declared in a Java interface is by default final. An abstract class may contain non-final variables.


3.Members of a Java interface are public by default. A Java abstract class can have the usual flavors of class members like private, protected, etc..


4.Java interface should be implemented using keyword “implements”; A Java abstract class should be extended using keyword “extends”.


5.An interface can extend another Java interface only, an abstract class can extend another Java class and implement multiple Java interfaces.


6.A Java class can implement multiple interfaces but it can extend only one abstract class.


7.Interface is absolutely abstract and cannot be instantiated; A Java abstract class also cannot be instantiated, but can be invoked if a main() exists.


8.In comparison with java abstract classes, java interfaces are slow as it requires extra indirection.

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Subject: Java

Q:

What were the most memorable accomplishments at your last job ? In your Carrer?

Answer

Focus on your most recent accomplishments, those in your current position or the job you had just prior to this one. But make sure they are relevant to the position for which you're interviewing.

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Q:

What is the similarity between Dynamic Binding and linking?

Answer

Dynamic binding is orthogonal to dynamic linking. Binding refers to the linking of a procedure call to the code to be executed in response to the call. Dynamic binding It is associated with polymorphism and inheritance, it(also known as late binding) means that the code associated with a given procedure call is not known until the time of the call at run-time.

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Subject: Java

Q:

What is the common usage of serialization? What exceptions occur during serialization?

Answer

The object need to be serialized when it’s sent over a network and when it’s state is saved. Exceptions which occur during serialization are:


a. transient fields


b. when the base class is serialized then only base class fields are handled.


c. static fields are ignored because they are not part of any state.

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Subject: Java

Q:

What is the SimpleTimeZone class?

Answer

SimpleTimeZone is a concrete subclass of TimeZone class. The TimeZone class represents a time zone, that is to be used with Gregorian calendar.


The SimpleTimeZone is created by using the base time zone offset from GMT time zone ID and rules, for starting and ending the time of daylight.

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Subject: Java

Q:

What is the Dictionary class?

Answer

- The Dictionary class is an abstract class.


- Classes like Hashtable which map keys to values inherit from this class. 


- An object can be looked for if a dictionary and a key is provided.


- Any non-null object can be used as a key and as a value.

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Subject: Java