Interview Question and Answers | Search Coding Interview Questions

Interview Questions and Answers - Order By Newest

Q991. What doesn Http keep alive header does ?

Ans. Http is connection less by default. header informs hosts to keep the connection alive so that the same connection can be reused for multiple communication.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java http http-alive client server communication}

Q992. What is the difference between Data Type and Data Structure ?

Core Java

Ans. Data type: a set of values together with operations on that type
Data structure: a physical implementation of a data type

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops data structure data type}

Q993. Is it correct to say that Interfaces are abstract data types ?

Ans. No.

Data Type holds data whereas Interface doesn't hold anything. Interface is a contract about how to communicate with the underlying Class.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java interface data type}

Q994. Do you see Class as a Data Type or Data Structure ?

Ans. Class can be better seen as Data Type. This could be implemented as a Data Structure too in some cases.

One thing worth understanding here is that Data type and Data structure are conceptual things. Class could be implementation of either of these.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java oops class data type data structure}

Q995. How many elements will be there in TreeSet after the last line and Why ?

TreeSet set = new TreeSet();
set .add(new String("abc"));
set .add(new String("abc"));

Core Java

Ans. One.

As we haven't specified the type of TreeSet, it being evaluated with the first element insertion. Once it's identified that it's of type String and as no comparator has been defined, the comparison is done using the String compareTo method. String compareTo method compares the elements by the content / value.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java set treeset string compareto coding code}

Q996. Which of the following data type you will prefer to store price - BigDecimal or Double ?

Ans. BigDecimal if memory and Performance is not critical concern, otherwise double.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java data types double bigdecimal}

Q997. Which takes more memory - float or Float ?

Core Java

Ans. float is a native data type whereas Float is a class. A Float object will always take more memory than float variable as there are metadata overheads with the objects.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java data type float Asked in 3 Companies basic frequent}

Q998. Difference between HashMap and WeakHashMap ?

Ans. WeakHashMap uses weak reference for keys, which means if the key object doesn't have any reference then both key/value mapping will become eligible for garbage collection.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java collections hashmap weakhashmap difference between garbage collection ebay}

Q999. Which tree is used to implement TreeMap in Java?

Ans. Red Black Tree

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java collections treemap map expert}

Q1000. What is collision in hash collections ?

Core Java

Ans. Collision is the situation when two different elements have the same Hash Code.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java collections collision hashcode hash code hash collections ebay Asked in 1 Companies intermediate frequent}

Q1001. When are static and instance methods resolved ? During compile time or Runtime ?

Ans. Static methods are resolved during compile time and hence they cannot participate in runtime polymorphism. Instance methods are resolved during runtime.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java static methods methods runtime polymorphism intermediate}

Q1002. What will the following code result ?

List> intList = new ArrayList>();

intList.add(Optional.empty());
intList.add(Optional.of(2));
intList.add(Optional.of(3));
intList.add(Optional.of(4));

System.out.println(intList.get(null));

Ans. Compile time error at last line as the get method expect argument of type native int.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve arraylist list coding collections}

Q1003. What will the following code result ? Will it compile ?

List> intList = new ArrayList>();

intList.add(Optional.empty());
intList.add(Optional.of(2));
intList.add(Optional.of(3));
intList.add(Optional.of(4));

System.out.println(intList.get((Integer)null));

Ans. Yes but the last line will throw NullPointerException upon execution.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve collections arraylist list coding}

Q1004. What will be the output ?Integer a = 10, b =10;Integer c = 10, d = 1000;System.out.println(a == b);System.out.println(c ==d);

Core Java

Ans. truefalse

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java coding equality object equality}

Q1005. How to determine if the linked list has a cycle in it ?

Ans. http://stackoverflow.com/questions/494830/how-to-determine-if-a-linked-list-has-a-cycle-using-only-two-memory-locations

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve linked list data structure algorithm java ebay}

Q1006. Can we have multiple classes in single file ?

Ans. Yes, but there can be only 1 public class in a single file.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java classes}

Q1007. What is OutOfMemoryError in Java?

Core Java

Ans. OutOfMemoryError in Java is a subclass of VirtualMachineError and is thrown by JVM when it runs out of heap memory.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve outofmemoryerror error exceptions jvm java heap memory heap}

Q1008. What is Apache Kafka ?

BigData

Ans. Kafka is a distributed, partitioned, replicated commit log service. It provides the functionality of a messaging system through messages being written to logs.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve kafka bigdata message queue Asked in 4 Companies}

Q1009. What is a broker in Apache Kafka ?

Ans. Kafka is run as a cluster comprised of one or more servers each of which is called a broker

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve kafka bigdata message queue}

Q1010. What is a Topic in Apache Kafka ?

Ans. A topic is a category or feed name to which messages are published

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve kafka bigdata message queue}

Q1011. Do you know of any facility to convert between Scala and Java Util Collections ?

Scala

Ans. We can use JavaConversions which is a part of Scala Library.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve scala scala collections java collections}

Q1012. Have you used Kafka in your project ? If Yes, for what ?

Ans. We were using Kafka as a replacement for JMS Message Queue for better throughput. We were just using a simple Java multi threaded client as order of message consumption didn't matter to us.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve kafka bigdata message queue java}

Q1013. Does Kafka uses ZooKeeper ?

Ans. Yes

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve kafka bigdata yes-no yes no}

Q1014. Which interfaces are implemented by BatchUpdateException?

Ans. [Iterable]

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java BatchUpdateException include}

Q1015. What is the package name for CertStoreParameters class?

Ans. java.lang

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve interfaces java CertStoreParameters include}

Q1016. Which is the Parent Class of CertStoreParameters class?

Ans. Clonable

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve interfaces java CertStoreParameters include}

Q1017. Action Class is singleton and hence not thread safe in ..

a. All versions of Struts
b. Struts 1
c. Struts 2
d. None of Struts versions

Ans. Struts 1

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve struts j2ee mvc frameworks struts1 struts2}

Q1018. Which is of the following is NOT TRUE for JVM ?

a. JVM reads Byte Code and generates Machine Code.
b. JVM is a virtual Machine that acts as a intermediary between Java Application and Host Operating System.
c. JVM reads Source Code and generates Byte Code.
d. JVM acts as a translator that translates different Machine code ( on the basis of Host Machine ) for a common Byte Code.

Ans. JVM reads Source Code and generates Byte Code.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java jvm}

Q1019. If we add Enum constants to a sorted collection ( Treemap , TreeSet ), What will be the order in which they will be maintained ?

a. Sorted Collection wont maintain them in any order.
b. Insertion Order
c. Order in which constants are declared.
d. Natural Sorting Order.

Ans. Order in which constants are declared.

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve enum collections sorted collections treemap treeset compareto comparable java}

Q1020. Which of the following is not type of inner classes ?

a. Simple Inner Class
b. Static Nested Inner Class
c. Method Nested Static Inner Class
d. Anonymous Inner Class

Ans. Method Nested Static Inner Class

Help us improve. Please let us know the company, where you were asked this question :

_{Like Discuss Correct / Improve java classes inner classes}

Try 1 Question(s) Test

Search Interview Questions

Help us and Others Improve. Please let us know the questions asked in any of your previous interview.