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Ans. REST or Representational State Transfer is a flexible architecture style for creating web services that recommends the following guidelines -

1. http for client server communication,
2. XML / JSON as formatiing language ,
3. Simple URI as address for the services and,
4. stateless communication.

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Q3. What will be the output of following Code ?

class BuggyBread {
   public static void main(String[] args) {
      String s2 = "I am unique!";
      String s5 = "I am unique!";

      System.out.println(s2 == s5);
   }
}

Ans. true, due to String Pool, both will point to a same String object.

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Q4. Name few Restriction Methods ?

Ans. eq, ge, gt , between, in , isNull, isEmpty, isNotnull, ne , like, lt , or , not

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Frequently asked question in companies using Rest Web services.

Q5. Different between POST and PUT in Rest

Ans. PUT requests are only meant to place the object as it is on server. For example - You want a file to be uploaded and then placed in a particular folder or you want an Employee object to be persisted in the table.

POST requests are also meant to transfer information from client to server but that information once received at the server is evaluated , modified or refactored before persisting.

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Q6. Should a DB Insert Request be a POST or PUT request in Rest

Ans. It depends on whether the request object is persisted as it is

or

its first dismantled, modified or refactored and then inserted into DB.

In first case, it should be a PUT request whereas in second case it should be a POST Request.

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Q7. How to specify the or/and combination restrictions within Criteria in Hibernate ?

Ans. session.createCriteria(Employee.class).add( Restrictions.or(Restrictions.like("name", "A%"),Restrictions.like("name", "B%"))).list();

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Q8. Can you name few matchers that can be used with hamcrest assertThat method ?

Junit

Ans. is
not
equals
anyOf
hasSize

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Q9. If given a choice , which one would you prefer to send params to the Get service , path params or query param ?

Web Service

Ans. If the number of params is quite large , I would prefer to either split it with majority of it in query params or all in query params.

If the params are all mandatory , I would keep it as path params. If it's optional , I would keep it as query param so as to keep consistent base url.

If we don't require the param name , then they can be kept as path params as query params necessitates the usage of param name.

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Q10. Is it necessary to specify "employeeId" with @PathParam("employeeId") in this case,

@Path("/{employeeId}")
public String employeeInfo(@PathParam("employeeId") Long employeeId){
}

Ans. No, it's optional as the name of path param required is same as method param name in this case.

Even the declaration as following should work -

@Path("/{employeeId}")
public String employeeInfo(@PathParam Long employeeId){
}

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Q11. Difference between stateless and stateful rest services ?

^{This question was recently asked at 'Sofi'.This question is still unanswered. Can you please provide an answer.}

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Q12. How can we create objects if we make the constructor private ?

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 block

Ans.d. We can create new object through static method or static block

Q13. What will be the output of executing following class ?

public class BuggyBread {

static {
System.out.println("Static Block");
}

{
System.out.println("Initialization Block");
}

BuggyBread(){
System.out.println("Constructor");
}

public static void main(String[] args){
System.out.println("Main Method");
}
}

a. Static Block
Main Method

b. Static Block
Instance Initialization Block
Main Method

c. Static Block
Constructor
Main Method

d. Static Block
Instance Initialization Block
Constructor
Main Method

Ans.a. Static Block
Main Method

Q14. What will be the output upon executing following class ?

public class BuggyBread {

static {
System.out.println("Static Block");
}

{
System.out.println("Instance Initialization Block");
}

BuggyBread(){
System.out.println("Constructor");
}

public static void main(String[] args){
System.out.println("Main Method");
new BuggyBread();
}
}

a. Instance Initialization Block
Constructor
Static Block
Main Method

b. Static Block
Instance Initialization Block
Constructor
Main Method

c. Main Method
Static Block
Instance Initialization Block
Constructor

d. Static Block
Main Method
Instance Initialization Block
Constructor

Ans.d. Static Block
Main Method
Instance Initialization Block
Constructor

Q15. With the following code, Which is a valid way to initialize ?
public class BuggyBread {

   private String element1;

   private String element2;

   private BuggyBread(String element1, String element2){
      this.element1 = element1;
      this.element2 = element2;
   }

   public static class Builder {

      private String element1;

      private String element2;

      Builder(BuggyBread buggybread){
         element1 = buggybread.element1;
         element2 = buggybread.element2;
      }

      Builder withElement1(String element1){
         this.element1 = element1;
         return this;
      }

      Builder withElement2(String element2){
         this.element2 = element2;
         return this;
      }

      BuggyBread build(){
         BuggyBread buggybread = new BuggyBread(element1,element2);
         return buggybread;
      }
   }
}

a. BuggyBread buggybread = new BuggyBread();

b. BuggyBread buggybread = new BuggyBread("element1","element2");

c. BuggyBread.Builder builder = new BuggyBread.Builder();

d. BuggyBread.Builder builder = new BuggyBread.Builder("element1","element2");

Ans.d. BuggyBread.Builder builder = new BuggyBread.Builder("element1","element2");

Q16. What will be the output of following ?

public class BuggyBread {

   private int x;
   private Integer y;

   BuggyBread(int x,int y){};

   public static void main(String[] args){
      BuggyBread buggybread = new BuggyBread(1,2);
      System.out.println(buggybread.x);
      System.out.println(buggybread.y);
   }
}    Reference

a. 0 0

b. 0 null

c. null 0

d. null null

Ans.b. 0 null

Q17. Which of the following is true for == operator ?

a. For primitives, == checks if the variables on left and right have same data type

b. For primitives, == checks if the variables on left and right have same value

c. For Objects, == checks if the references on left and right have same data type

d. For Objects, == checks if the references on left and right have same value

Ans.b. For primitives, == checks if the variables on left and right have same value

Q18. Which of the following is equivalent to following logic ?

Not X && Not Y

a. x || Y

b. Not(X || Y)

c. Not(X && Y)

d. Not X && Y

Ans.b. Not(X || Y)

Q19. Which of the following http response means the resource is not found ?

Java EE

a. 500

b. 200

c. 404

d. 400

Ans.c. 404

Q20. What is Dirty Read in Database Transactions ?

Database

a. Data Read by Transaction 2 which hasn't yet updated by Transaction 1

b. Data Read by Transaction 2 which has been updated and commited by Transaction 1

c. Data Read by Transaction 2 which has been updated but not commited by Transaction 1

d. Inability of Transaction 2 to read Data when Transaction 1 is updating.

Ans.c. Data Read by Transaction 2 which has been updated but not commited by Transaction 1

Q21. Which of following annotation is used to initialize objects before executing set of tests ? Reference

Junit

a. @Test

b. @Ignore

c. @After

d. @Before

Ans.d. @Before

Q22. Which of the following is not true for static keyword ? Reference

a. Static members are shared by all objects of the class.

b. We can override static methods.

c. Static methods operate on static variables only.

d. Static Elements are accessed using class name.

Ans.b. We can override static methods.

Q23. What is Lazy Initialization in Hibernate ? Reference

a. Feature to load the dependencies from Cache

b. Feature to load all objects and relationships in advance before they can be used

c. Feature to not load dependencies and relationship in advance and load when required

d. Feature to not load the dependencies and relationships at all

Ans.c. Feature to not load dependencies and relationship in advance and load when required

Q24. Which of the following is not the benefit of Lazy Initialization in Hibernate ?

a. Laod When required provides better performance

b. Object stays lighter

c. Less number of Database calls

d. Less load on Database

Ans.c. Less number of Database calls

Q25. The use of volatile keyword facilitates ..

a. Making Use of Cache for better Performance

b. Avoiding use of Cache

c. Making use of Backward as well as Forward Cache

d. Keeping only one copy of variable in Cache

Ans.b. Avoiding use of Cache

Q26. Static Polymorphic in Java is achieved through ..

a. Method Overloading

b. Method Overriding

c. Variable Overloading

d. Variable Overriding

Ans.a. Method Overloading

Q27. Which of following are serialized ?

a. static variables

b. transient variables

c. instance variables

d. method local variables

Ans.c. instance variables

Q28. Which of the following is not true for Hibernate Cache ?

a. First level cache is enabled by default

b. First level Cache is Session specific

c. First level cache is considered global

d. First level Cache came with Hibernate 1.0

Ans.c. First level cache is considered global

Q29. Which of the following is not an Hibernate Annotation