Interview Questions and Answers for 'Function' - 20 question(s) found - Order By Newest Q1. Which of the following are valid declarations
1. void method(int... x){};
2. void method(int.. x){};
3. void method(int.. .x){};
4. void method(int ...x){};
5. void method(int... x){};
6. void method(int ... x){};
7. void method(int x, int... y){};
8. void method(int... x, int y){};
9. void method(int... x,int... y){};
Core Java 2017-05-22 21:22:57
Ans. 1st is a valid and standard declaration.
2nd results in compilation error as only 2 dots are there.
3rd results in compilation error as three dots are not consecutive and broken.
4 through 6 may not be standard and ideal way of declarations but they are valid and will compile and work fine.
7 is valid declaration.
8 and 9 will result in compilation error as var args can only be provided to last argument. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods functions method declaration scjp ocjp Q2. Difference between parameters and arguments ? Core Java Admin info@buggybread.com
Ans. Parameters are the variables that the method is expected to receive along with the method call. Arguments are the values which are passed on while calling the methods. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve parameter argument method function java basic Q3. What is the difference between these two method declarations ?
private static void method(String[] arg)
and
private static void method(String... arg) Core Java 2017-05-23 08:41:54
Ans. First expects the argument as a string array whereas second expects variable number of string arguments or a string array.
So we can call both by providing string array as an argument but second can be called with 0 to n string arguments which cannot be done for first.
for example - We can call second method with any of following
method();
method("Hello");
method("Hello","World");
method(new String[4]);
Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q4. Can we overload method as following ?
void method(int... x){};
void method(int[] x){}; Core Java 2017-05-22 21:27:42
Ans. No. Because java internally treats var args as arrays and hence both method declarations will generate the same byte code and hence would result in ambiguity while determining call binding. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods functions method declaration scjp ocjp Not frequently asked as it was introduced with Java 8. Q5. What is the @FunctionalInterface annotation ? Core Java Admin info@buggybread.com
Ans. This is an informative annotation that specify that the interface is a functional interface. A Function Interface has only one abstract method and many default methods. Compiler generates an error if the interface specified with the annotation doesn't abide by the specifications for functional interface. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve java java8 java 8 functional interface default methods Q6. What is the input to the Reduce function ? a. One Key and One Value b. Multiple Keys and Multiple associated Values c. Multiple Keys and One associated values with each d. One key and associated values. Anonymous
Ans. One key and associated values. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve hadoop bigdata big data map-reduce map reduce reduce function Q7. How are values passed in Java ? By value or reference ?
Ans. Java only provides pass by value. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve ebay pass by value pass by reference method call methods functions function call Trustwave basic   frequent Q8. What are instance methods ? 2016-06-03 10:07:50
Ans. All methods defined in a class that are not marked static are actually instance methods. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve methods functions Q9. What are the advantages of using methods in Java ? Core Java 2017-03-10 10:46:34
Ans. Likewise classes, methods also provide a way for code reuse and abstraction. Code is reused, clean and easy to understand if classified properly within classes and methods. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve methods functions advantages of methods in java Do you think these are the Best Java Frameworks ? OpenXava SPRING MVC Apache Stripes Check everything that is Best in Java Click Here
Q10. What are var args ?
or
What is the use of var args ? Core Java 2017-05-22 21:16:41
Ans. Var args is the feature of Java that allows a method to have variable number of arguments. Var args are used when we are not sure about the number of arguments a method may need. Internally java treats them as array.
Declarations of methods with var args
void method(int... x){};
void method(int x, int... y){}; Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods functions method declaration Hexaware Bosch Q11. Why following method declarations are not valid ?
void method(int... x, int y){};
void method(int... x,int... y){}; Core Java 2017-05-22 21:25:36
Ans. Because var args are not only allowed with the last argument in the method declaration. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods functions method declaration ocjp scjp Q12. Which method will get called if we call it as method(1)
void method(int x ){};
void method(int... x){}; Core Java 2017-05-22 21:32:17
Ans. Though the call an be bind to either of these but in this case, 1st method will get priority and hence will be called. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args method function overloading scjp ocjp Q13. Do you see any problem with this code
public class BuggyBread {
public static void main(String[] args) {
method("Hello","World");
}
private static void method(String... args){
for(String arg:args){
System.out.println(arg);
}
}
} Core Java 2017-05-23 08:29:28
Ans. No, It will compile and execute perfectly fine. As we are using method with var args , we can call it with 0 to n arguments. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q14. Do you see any problem with this code
public class BuggyBread {
public static void main(String[] args) {
method();
}
private static void method(String... args){
for(String arg:args){
System.out.println(arg);
}
}
} Core Java 2017-05-23 08:30:09
Ans. This will compile fine as we can provide 0 arguments for a var arg but will print nothing upon execution. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q15. Do you see any problem with this code
public class BuggyBread {
public static void main(String[] args) {
method("Hello");
}
private static void method(String... args){
for(String arg:args){
System.out.println(arg);
}
}
private static void method(String arg){
System.out.println(arg);
}
} Core Java 2017-05-23 08:32:25
Ans. It will compile fine and the method call will bind to method with specific argument and not with var arg
i.e private static void method(String arg)
It will print "Hello" upon execution Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q16. Do you see any problem with this code
public class BuggyBread {
public static void main(String[] args) {
method("Hello");
}
private static void method(String... args){
for(String arg:args){
System.out.println(arg);
}
}
private static void method(String[] arg){
System.out.println(arg);
}
} Core Java 2017-05-23 08:33:56
Ans. Yes, it will give compilation error and java will complain about duplicate method. Java treat var args internally as arrays and hence would result in same byte code for both method's syntax. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q17. Will this code work
public class BuggyBread {
public static void main(String[] args) {
method("Hello","World");
}
private static void method(String[] arg){
System.out.println(arg);
}
}
What all possible changes we can make to method signature to make it work ? Core Java 2017-05-23 08:36:19
Ans. It won't work as java won't find the method definition for method with 2 arguments.
We can either declare the method as
private static void method(String arg,String arg2)
or
private static void method(String... arg) Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q18. Do you prefer using var args ? Core Java 2017-05-23 09:04:40
Ans. Though var args are used rarely but they are pretty useful if a method is expected to receive variable number of arguments. For example - it's pretty useful for the main method as the caller has the flexibility to provide arguments in infinite ways.It provides a convenience and flexibility to the caller. Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve var args methods method declarations functions Q19. In the Following code which foo will get called.
foo(Integer i){
}
foo(String s){
}
public static void main(){
passing foo(null);
} Core Java 2018-01-21 17:16:39
Ans. ambiguity error Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve code method function data types EPAM Do you think these are the Best Java Frameworks ? OpenXava SPRING MVC Apache Stripes Check everything that is Best in Java Click Here
Q20. How do you define a functional interface? Core Java 2018-01-22 17:32:13
Ans. Create interface with the only one non-overriding abstract method and annotate it with @FunctionalInterface Help us improve. Please let us know the company, where you were asked this question : Like Discuss Correct / Improve functional interface java 8 Adobe