Search Interview Questions | More than 3000 questions in repository. There are more than 900 unanswered questions. Click here and help us by providing the answer. Have a video suggestion. Click Correct / Improve and please let us know. |
|
| ||||
Interview Questions and Answers - Order By Newest | ||||
| ||||
Ans. Simple Inner Class, Local Inner Class, Anonymous Inner Class, Static Nested Inner Class. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   inner classes   classes Asked in 6 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
Frequently asked in Indian Service Companies. Tech Mahindra ( Based on 3 inputs ) and Infosys ( 3 inputs ) | ||||
| ||||
Ans. List - Members are stored in sequence in memory and can be accessed through index. Set - There is no relevance of sequence and index. Sets doesn't contain duplicates whereas multiset can have duplicates. Map - Contains Key , Value pairs. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   collections   list   set   map   list vs set vs map Asked in 8 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
| ||||
Ans. Java doesn't support multiple inheritance. Interfaces does't facilitate inheritance and hence implementation of multiple interfaces doesn't make multiple inheritance. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oop   oop concepts   inheritence   multiple inheritence   basic interview question Asked in 10 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
Frequently asked at HCL Technologies ( Based on 3 feedback ) | ||||
| ||||
Ans. Checked exceptions are the exceptions for which compiler throws an errors if they are not checked whereas unchecked exceptions are caught during run time only and hence can't be checked. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   exceptions   checked exceptions   unchecked exceptions   exception handling   checked vs unchecked exceptions Asked in 39 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
Very frequently asked. Favorite question in Walk in Drive of many Indian service companies. | ||||
| ||||
Ans. Final variable is a variable constant that cannot be changed after initialization. | ||||
Sample Code for final variable | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  oops   java   final   final variable   basic interview question Asked in 12 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
| ||||
Ans. Abstract classes are only meant to be sub classed and not meant to be instantiated whereas concrete classes are meant to be instantiated. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   abstract classes   Abstract vs Concrete Class Asked in 1 Companies basic   frequent | ||||
| ||||
Ans. Vectors are synchronized whereas Array lists are not. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   basic interview question   vector   arraylist   collections   synchronization   vector vs arraylist Asked in 35 Companies basic   frequent | ||||
| ||||
Ans. It in Java is used to indicate that a field should not be serialized. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   serialization   transient   java keywords Asked in 39 Companies intermediate   frequent | ||||
Try 2 Question(s) Test | ||||
Very Frequently asked. Usually asked along with String Class related questions. | ||||
| ||||
Ans. Class using which only immutable (objects that cannot be changed after initialization) objects can be created. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   immutable  immutability   immutable  immutability class   string class   basic interview question Asked in 18 Companies Basic   frequent | ||||
Try 2 Question(s) Test | ||||
Frequently asked to fresh graduates and less experienced. | ||||
| ||||
Ans. Inheritance. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  inheritance  object oriented programming (oops)  oops concepts   java   oops   composition  object oriented programming (oops)  oops concepts Asked in 1 Companies basic   frequent | ||||
Very frequently asked in phone and walk in interviews. | ||||
| ||||
Ans. An interface without any method declaration is called as marker interface. there are 3 in-built interfaces in JVM i.e. serializable, clonable, remote | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   interfaces   marker interface   serializable   clonable Asked in 21 Companies intermediate   frequent | ||||
Try 1 Question(s) Test | ||||
Frequently asked to fresh graduates. | ||||
| ||||
Ans. Process is a program in execution whereas thread is a separate path of execution in a program. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   threads   multi threading   operating system   process vs thread Asked in 24 Companies basic   frequent | ||||
| ||||
Ans. Autoboxing is the automatic conversion that the Java compiler makes between the primitive types and their corresponding object wrapper classes | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   java5   autoboxing   wrapper classes Asked in 2 Companies basic   frequent | ||||
Very frequently asked. Usually difference between String,StringBuffer and StringBuilder is asked in different variations. | ||||
| ||||
Ans. StringBuffer is synchronized whereas StringBuilder is not. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   string   stringbuffer   string class   stringbuilder   synchronized   basic interview question   infosys technologies Asked in 17 Companies basic   frequent | ||||
Try 1 Question(s) Test | ||||
| ||||
Ans. It is the process of examining / modifying the behaviour of an object at runtime. | ||||
Sample Code for reflection | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   reflection   reflection api   ebay   mindtree Asked in 29 Companies basic   frequent | ||||
| ||||
Ans. As we only downcast class in the hierarchy, The ClassCastException is thrown to indicate that code has attempted to cast an object to a subclass of which it is not an instance. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   class casting   classcastexception   exception   error Asked in 4 Companies intermediate   frequent | ||||
Try 2 Question(s) Test | ||||
| ||||
Ans. Both belong to the class as a whole and not to the individual objects. Static methods are explicitly called for execution whereas Static block gets executed when the Class gets loaded by the JVM. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   oops   static   static method   static block   difference between   similarity basic   frequent | ||||
Try 1 Question(s) Test | ||||
| ||||
Ans. Yes, but the overloaded main methods without single String[] argument doesn't get any special status by the JVM. They are just another methods that needs to be called explicitly. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   main method   overloading   yes-no Asked in 6 Companies intermediate   frequent | ||||
Very Frequently asked. | ||||
| ||||
Ans. throw is used to re throw an exception.throws is used to declare that the method throws the respective exceptions.try block is used to identify if the respective block has thrown any exception.catch is used to catch the exception that has been thrown by the respective try block. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   exception handling   throw   throws   try   catch Asked in 5 Companies basic   frequent | ||||
Usually asked to experienced developers. | ||||
| ||||
Ans. A has dependency of B, B has dependency of C and C has dependency of A With Maven 2 , came transitive dependency wherein in above scenario, C will acts as a dependency of A as if this dependency has been defined directly in A but the negative side is that if it leads to cyclic dependency , it creates problems. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  maven   dependencies   cyclic dependencies   transitive dependencies   build management Asked in 1 Companies   frequent | ||||
| ||||
Ans. GET is supposed to get information from the server. Client sends the minimal information so that Server can respond with the response body on basis of request. For example - You want to get complete employment record for employee id 123 POST is supposed to send the information for submission. Payload or a Body is usually sent so that it can be persisted on the server. For example - Sending the complete information of an employee ( id, name , dept etc ) to the server for persisting it. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  get vs post   web service   rest Asked in 11 Companies basic   frequent | ||||
| ||||
Ans. Coupling is the degree of interdependence between software modules, a measure of how closely connected two modules are or the strength of the relationships between modules. Cohesion refers to the degree to which the elements of a module belong together. Cohesion measures the strength of relationship between pieces of functionality within a given module. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  coupling  cohesion Asked in 10 Companies   frequent | ||||
Frequently asked Generic Question. | ||||
| ||||
Ans. [Open Ended Answer] Usually answered stating your keen interest in the role offered and challenges and opportunities the role offers. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve   Asked in 42 Companies   frequent | ||||
| ||||
Ans. class A { void test() { System.out.println("test() method"); } } class B { void test() { System.out.println("test() method"); } } Suppose if Java allows multiple inheritance like this, class C extends A, B { } A and B test() methods are inheriting to C class. So which test() method C class will take? As A & B class test() methods are different , So here we would Facing Ambiguity. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  multiple inheritance  object oriented programming (oops)  oops concepts  diamond problem Asked in 20 Companies basic   frequent | ||||
Usually asked to entry level software developers. | ||||
| ||||
Ans. public static void main(String[] args) { int num1 = 1; int num2 = 2; num1 = num1^num2; num2 = num1^num2; num1 = num1^num2; System.out.print("num1 = " + num1 +", num2 = "+num2); } | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  code  coding Asked in 37 Companies basic   frequent | ||||
| ||||
Ans. JSON is "JavaScript Object Notation", primarily used for client-server or server-server communication. Its a much lighter and readable alternative to XML. JSON is language independent and is easily parse-able in all programming languages. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  json   markup language   client server communication Asked in 26 Companies basic   frequent | ||||
Try 2 Question(s) Test | ||||
| ||||
Ans. An API is a kind of technical contract which defines functionality that two parties must provide: a service provider (often called an implementation) and an application. an API simply defines services that a service provider (i.e., the implementation) makes available to applications. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  j2ee   api   java basic   frequent | ||||
| ||||
Ans. HTTP or Hypertext Transfer Protocol is internet protocol for tranmission of hypertext ( text with meta data ) over internet. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  j2ee   http   internet  fidelity Asked in 2 Companies basic   frequent | ||||
| ||||
Ans. For top level class we can only use "public" and "default". We can use private with inner class. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   class   access specifier   inner classes basic   frequent | ||||
| ||||
Ans. Threads in Java can be implement either by Extending Thread class or implementing runnable interface. | ||||
Help us improve. Please let us know the company, where you were asked this question : | ||||
Like Discuss Correct / Improve  java   threads   multi threading Asked in 1 Companies basic   frequent | ||||