Java Interview Questions and Answers

What is an Iterator interface?
The Iterator interface is used to step through the elements of a Collection .
Which java.util classes and interfaces support event handling?
The EventObject class and the EventListener interface support event processing.
What is the GregorianCalendar class?
The GregorianCalendar provides support for traditional Western calendars
What is the SimpleTimeZone class?
The SimpleTimeZone class provides support for a Gregorian calendar .
What is the Map interface?
The Map interface replaces the JDK 1.1 Dictionary class and is used associate keys with values.
What is the highest-level event class of the event-delegation model?
The java.util.EventObject class is the highest-level class in the event-delegation class hierarchy.
What is the Collection interface?
The Collection interface provides support for the implementation of a mathematical bag - an unordered collection of objects that may contain duplicates.
What is the Set interface?
The Set interface provides methods for accessing the elements of a finite mathematical set. Sets do not allow duplicate elements. .
What is the difference between the size and capacity of a Vector?
The size is the number of elements actually stored in the vector, while capacity is the maximum number of elements it can store at a given instance of time.
Can a vector contain heterogenous objects?
Yes a Vector can contain heterogenous objects. Because a Vector stores everything in terms of Object.
Can a ArrayList contain heterogenous objects?
Yes a ArrayList can contain heterogenous objects. Because a ArrayList stores everything in terms of Object.
What is an enumeration?
An enumeration is an interface containing methods for accessing the underlying data structure from which the enumeration is obtained. It is a construct which collection classes return when you request a collection of all the objects stored in the collection. It allows sequential access to all the elements stored in the collection. Considering the basic properties of Vector and ArrayList, where will you use Vector and where will you use ArrayList? The basic difference between a Vector and an ArrayList is that, vector is synchronized while ArrayList is not. Thus whenever there is a possibility of multiple threads accessing the same instance, one should use Vector. While if not multiple threads are going to access the same instance then use ArrayList. Non synchronized data structure will give better performance than the synchronized one.
Describe synchronization in respect to multi-threading?

With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchronization, it is possible for one thread to modify a shared variable while another thread is in the process of using or updating same shared variable. This usually leads to significant errors. 

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Child Development & Pedagogy

The child will be able to use proper sentences by the age of?

Indian Politics

______is an institutional mechanism to provide representation to the states of India?

Books and Authors

Which text is not written by Kalidasa?

Indian Constitution

Which Constitutional Amendment introduced Right to Education as a Fundamental Right?

Indian History

Which animal is engraved on Harappan seals?

Indian Politics

Who is known for initiating electoral reforms in India to ensure free and fair elections?

Indian Constitution

The sequence in which the given terms are mentioned in the preamble to the Constitution of India is?

Which of the following parts of the Constitution of India provides fundamental rights ?

Books and Authors

Who among the following is the author of ‘Politics’?

Which one is the text not written by Abul Fazl?

Which King was the author of Ratnawali, Nagananda, Priyadarsika?

Fill in the blank

Fill in the blanks with the most appropriate preposition in the given sentence.
The class begins _______ 7:30 am _____ the morning.

The workers were so skilled that their _____ was quite visible even to a layman.


Choose appropriate article for the given sentence:
______ German is ___ easy language to learn for English speaking students.


What will be the synonym of ‘Eradicate’?

What will be the synonym of the word ‘disaster’?

Pipes and Cistern

Three taps A,B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternatively, the tank will be full in?

Two pipes A and B can fill a tank in 6 hours and 4 hours respectively. If they are opened on alternate hours and if pipe A s opened first, in how many hours, the tank shall be full?

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पंजाब स्टेट पावर कॉर्पोरेशन लिमिटेड Punjab State Power Corporation Limited (PSPCL) - 2632 पद - 20/06/2021 अंतिम तिथि

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