Interview Questions and Answers - Order By Rating Q2761. Write a program for Coin Changer application ?
Ans. http://javasearch.buggybread.com/CodeSnippets/searchCodeSamples.php?&category=code&searchOption&keyword=979 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  coin changer application  coin changing  general electic (ge) Q2762. What will be the output of following code ?
System.out.println((int)'a');
Ans. The ascii value of a i.e 97 Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  character  ascii Q2763. What will be the output of
System.out.println((Integer)'a');
Ans. It will result in compilation error as primitive char cannot be casted to Integer object, alternatively we can cast it to primitive int like following
System.out.println((int)'a'); Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  character  ascii Q2764. What is unmodifiable set / unmodifiable map ? How can we create one ?
Ans. It is an unmodifiable / read only view of the underlying collection. We can use
Collections.unmodifiableSet(Set set)
Collections.unmodifiableMap(Map map)
Collections.unmodifiableCollection(Collection collection) Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections  set  unmodifiable set  map  unmodifiable map  unmodifiablemap  unmodifiableset  Collections.unmodifiableCollection  Collections.unmodifiableMap  Collections.unmodifiableSet Q2765. What is the use of MethodHandle ?
Ans. MethodHandle is a modern, more flexible, more typesafe way of doing reflection. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  MethodHandle  Reflection Q2766. What is a Destructor ? Do we have Destructors in Java ? Core Java
Ans. Destructor is used to de-allocate memory allocated by objects.
There are no destructors in Java. Alternatively, Java provides Automatic garbage collection i.e automatically releasing the un-referenced memory. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  destructor  garbage collection Asked in 11 Companies Basic   frequent Try 1 Question(s) Test Q2767. What are JSP Scriptlets?
Ans. Scriptlet allow to write Java code inside JSP like following
<% Java Code %> Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  jsp  jsp scriptlet  scriptlet Q2768. What is use of Revert in SVN? Tools
Ans. Revert your local changes.
There are 2 types of reverts -
1) Local Revert: It will delete all changes from files which you made after updates and before commit.
2) Repo Revert: Upload the changes to previous Repo. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  svn  subversion  version control system  configuration management Asked in 2 Companies Q2769. Can we have multiple threads consuming message stream from a single partition ?
Ans. Yes, by having multiple Consumer Groups. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  apache kafka  kafka  kafka consumer  kafka topic partitions  bigdata  consumer group Q2770. Can we have multiple threads consuming messages from a single partition if we have single Consumer Group ?
Ans. No, we can only have max 1 thread per partition in a single Consumer Group. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  apache kafka  kafka  kafka consumer  kafka topic partitions  bigdata  consumer group Q2771. If we have more threads than partitions in a kafka consumer, How can we model it efficiently ?
Ans. We will have to use multiple consumer groups in that case as threads will remain idle if we use single consumer group. A more sophisticated algorithm could be required with multiple groups if we have to ensure the order of consumption. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  apache kafka  kafka  kafka consumer  kafka topic partitions  bigdata  consumer group Q2772. Why Java is not considered pure OOP's language ? Core Java
Ans. There are 2 reasons for it.
1. Usage of Primitive types - Though Java provides classes for the primitive data types but as the usage of primitives is permissible, its considered unpure OOP's language.
2. Usage of Static members - Static members belong to the class and not objects and hence not considered fit for pure OOP's programming. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  oops  object oriented programming  object oriented language  primitive data types Asked in 2 Companies Q2773. Is Iterator a class ?
Ans. No, iterator is an interface that is used to parse through the elements of a Collection Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  collections  iterator Q2774. Can a lock be acquired on a class? How is it different than the object level lock ?
Ans. Yes, a lock can be acquired on the class. Class level lock is applicable on the whole class and hence on all objects of the class whereas the object level lock is applicable on the respective object. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  synchronization  class level lock  object level lock Q2775. What is the use of Runtime Class ?
Ans. This class is used to provide access to the Java runtime system Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  runtime class  jre  java runtimeFrequently asked. Q2776. What should a class do if its implementing an interface ? Core Java
Ans. It should either implement all interface methods or declare unimplemented methods as abstract. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  interfaces Asked in 1 Companies Basic   frequent Try 1 Question(s) Test Q2777. What should a class do if its extending an abstract class ? Core Java
Ans. It should either implement the abstract methods or re-declare them abstract. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  abstract class Asked in 2 Companies Basic   Frequent Q2778. What is a compilation unit in Java ?
Ans. Java Source Code File Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  compilation unit in java Q2779. What is Associativity while evaluating a Java statement ? Core Java
Ans. Associativity determines whether an expression is evaluated left-right or right-left. When an expression has two operators with the same precedence, the expression is evaluated according to its associativity. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  associativity  expression evaluation  operator Q2780. What is a package and what are its advantages ? Core Java
Ans. Package is a namespace that organizes a set of related classes.
Advantages of Packages
1. Better Organization of classes.
2. Saves from the problem of duplicate names as duplicate class names are allowed across different packages. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve  package  advantages of packages Asked in 1 Companies Basic Q2781. When String literals are compared using ==, they always returns true if the string values are same because .. Reference Core Java
a. of overridden compareTo method b. of overridden compare method c. of String Pool d. == means that the object contents are equalAns.c. of String Pool
Q2782. Which of the following is true ? Core Java
a. Composition is Tightly Bound b. Inheritance is Tightly Bound c. Object can only hold reference of only one other object d. A Class cannot be extended by multiple classesAns.b. Inheritance is Tightly Bound
a. x==y on all literals always returns false b. x.equals(y) on all literals always returns false c. if x.equals(y) returns true, x==y returns true too d. if x.equals(y) returns false, x==y returns trueAns.c. if x.equals(y) returns true, x==y returns true too
a. Constructor without parameters declared by user b. Constructor provided by Java if no constructor is declared c. Constructor with empty body d. All of the aboveAns.b. Constructor provided by Java if no constructor is declared
Q2785. How can we create objects if we make the constructor private ? Core Java
a. We can't create objects if constructor is private b. We can only create objects if we follow singleton pattern c. We can only create one object d. We can create new object through static method or static blockAns.d. We can create new object through static method or static block
Q2786. What will be the output of following ?
String str1 = new String("String1");
String str2 = new String("String1");
System.out.print(str1 == str2);
System.out.print(str1.equals(str2));
str1 = str2;
System.out.print(str1 == str2); Core Java
a. falsetruetrue b. truetruetrue c. truetruefalse d. falsetruefalseAns.a. falsetruetrue
Q2787. What will be the output of following code ?
String str1 = "String1";
String str2 = "String1";
System.out.print(str1 == str2);
System.out.print(str1.equals(str2));
str1 = str2;
System.out.print(str1 == str2); Core Java
a. falsetruetrue b. falsefalsetrue c. truetruetrue d. falsefalsefalseAns.c. truetruetrue
Q2788. What will be the output of following code ?
String str1 = "String1";
String str2 = "String2";
str1.concat("String3");
System.out.print(str1);
System.out.print(str2);
Core Java
a. String1String2 b. String1String3String3 c. String1String3String1String3 d. String1String1Ans.a. String1String2
Q2789. What will be the output of following code ?
String str1 = "String1";
String str2 = "String2";
str1=str1.concat("String3");
System.out.print(str1);
System.out.print(str2); Core Java
a. String1String2 b. String1String3String2 c. String1String2String3 d. String1Stringg3String1Ans.b. String1String3String2
Q2790. Which method needs to be implemented if a class is implementing comparable interface ? Core Java
a. comp b. compare c. compareTo d. compareEqualsAns.c. compareTo