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| Core%20java - Interview Questions and Answers for 'L' - 0 question(s) found - Order By Newest |
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|  Q1. 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. falsetruefalse |
| | Ans.a. falsetruetrue |
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| Q2. 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. falsefalsefalse |
| | Ans.c. truetruetrue |
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| | Q3. Which method needs to be implemented if a class is implementing comparable interface ? | Core Java |
| | a. comp | | b. compare | | c. compareTo | | d. compareEquals |
| | Ans.c. compareTo |
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| | Q4. Which of the following is false ? | Core Java |
| | a. A Class cannot override both hashcode and equals method. | | b. A class can override both hashcode and equals method. | | c. A Class must override hashCode method if its overridding equal method. | | d. A Class can override hashCode even if its not overridding equals method. |
| | Ans.a. A Class cannot override both hashcode and equals method. |
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| | | a. interface | | b. abstract class | | c. final class | | d. util class |
| | Ans.d. util class |
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| Q6. 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");
}
}
| Core Java |
| 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 |
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| Q7. 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();
}
}
| Core Java |
| 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 |
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| Q8. 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;
}
}
} | Core Java |
| | 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"); |
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| Q9. What will be the output of following code ?
public class BuggyBread {
private int x;
private int y;
BuggyBread(int x,int y){};
public static void main(String[] args){
BuggyBread buggybread = new BuggyBread();
System.out.println(buggybread.x);
}
}  Reference | Core Java |
| | a. 0 | | b. null | | c. compilation error due to uninitialized element | | d. compilation error due to constructor |
| | Ans.d. compilation error due to constructor |
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| Q10. 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 | Core Java |
| | a. 0 0 | | b. 0 null | | c. null 0 | | d. null null |
| | Ans.b. 0 null |
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| Q11. What will be the output of exceuting main method ?
public static void main(String[] args){
List list = new ArrayList();
list.add(1);
list.add(2);
list.add(3);
System.out.println(list);
} | Core Java |
| | a. 1,2,3 | | b. Order cannot be determined | | c. compilation error | | d. 3,2,1 |
| | Ans.a. 1,2,3 |
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| Q12. What will be the output upon executing main method ?
public static void main(String[] args){
Set set = new HashSet();
set.add(1);
set.add(2);
set.add(3);
System.out.println(set);
} | Core Java |
| | a. 1,2,3 | | b. Order cannot be determined | | c. Compilation error | | d. 3,2,1 |
| | Ans.b. Order cannot be determined |
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| | Q13. Which of the following is true for == operator ? | Core Java |
| | 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 |
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| Q14. Which of the following is equivalent to following logic ?
Not X && Not Y | Core Java |
| | a. x || Y | | b. Not(X || Y) | | c. Not(X && Y) | | d. Not X && Y |
| | Ans.b. Not(X || Y) |
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| | Q15. Optional has been introduced in Java 8 to get away with which of following exception ? Reference | Core Java |
| | a. ArithmeticException | | b. ParseException | | c. NullPointerException | | d. FileNotFoundException |
| | Ans.c. NullPointerException |
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| | | a. Abstract Class is only meant to be sub classed and not supposed to be instantiated. | | b. Abstract class handlers can be used to handle derived class objects. | | c. We can't have an abstract class without abstract methods. | | d. Abstract class has member elements. |
| | Ans.c. We can't have an abstract class without abstract methods. |
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| | | a. String | | b. StringBuffer | | c. StringBuilder | | d. None of these create immutable objects. |
| | Ans.a. String |
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| | | a. String | | b. StringBuffer | | c. StringBuilder | | d. None of these |
| | Ans.b. StringBuffer |
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| | Q19. Which of the following methods are used by Java Garbage Collection Mechanism ? | Core Java |
| | a. final | | b. finally | | c. finalize | | d. All of the above |
| | Ans.c. finalize |
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| | Q20. Which of the following about Garbage collection is false ? | Core Java |
| | a. We can call Garbage collection explicitly | | b. Garbage Collection guarantees that the application will not run out of memory | | c. finalize method is used by Java for Garbage Collection | | d. Garbage Collection Mechanism delete unclaimed objects that are no longer required |
| | Ans.b. Garbage Collection guarantees that the application will not run out of memory |
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| | | 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 |
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| | Q22. Which of the following is not the benefit of Lazy Initialization in Hibernate ? | 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 |
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| | Q23. Which of the following is not an advantage of JSON over XML ? Reference | JSON |
| | a. Lighter and Faster | | b. Object Representation | | c. Supports multiple data types | | d. Backward compatible with all XML applications |
| | Ans.d. Backward compatible with all XML applications |
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| | | a. Sorted in Ascending Order | | b. Sorted in Descending Order | | c. Sorted in any Order | | d. Unsorted |
| | Ans.c. Sorted in any Order |
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| Q25. The following code is an example of
public class Car extends Vehicle{
int x;
Car(int y){
x = 5;
}
Car(){
this(5);
}
} | Core Java |
| | a. Constructor Overloading | | b. Constructor Chaining | | c. Both Constructor Overloading and Chaining | | d. None of above |
| | Ans.c. Both Constructor Overloading and Chaining |
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| | Q26. The use of volatile keyword facilitates .. | Core Java |
| | 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 |
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| | Q27. Static Polymorphic in Java is achieved through .. | Core Java |
| | a. Method Overloading | | b. Method Overriding | | c. Variable Overloading | | d. Variable Overriding |
| | Ans.a. Method Overloading |
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| | Q28. Runtime Polymorphism in Java is achieved through .. | Core Java |
| | a. Method Overloading | | b. Method Overriding | | c. Variable Overloading | | d. Variable Overriding |
| | Ans.b. Method Overriding |
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| | Q29. Which of the following collections stores its elements in natural sorting order ? | Core Java |
| | a. HashMap | | b. LinkedHashMap | | c. TreeMap | | d. EnumMap |
| | Ans.c. TreeMap |
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| | Q30. Which of following stores its elements in natural Sorting Order ? | Core Java |
| | a. AbstractSet | | b. HashSet | | c. LinkedHashSet | | d. TreeSet |
| | Ans.d. TreeSet |
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