Core java interview questions and answers for 3-5 years experience

 Part 13

Core java interview questions and answers for 3-5 years experience covered in this post:

    What is the static method defined in Function functional interface?

-          There is only one static method defined inside the Function interface.

-          Identity() static method is defined in Function.

-          Returns a function that always returns its input argument.

-          You will get the same output as your input.

-          Please refer to the below example.

package simplifiedjava.crackedInterview.java8;  import java.util.Arrays; import java.util.List; import java.util.function.Function;  public class FunctionStaticMethodDemo {        public static void main(String[] args) {             List<String> list = Arrays.asList(".Net","Php","Java","C++","C","Database");             Function<String, String> f = Function.identity();             for(String s: list) {                   System.out.println(f.apply(s));             }       } } Output: .Net Php Java C++ C Database

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    What is the difference between Predicate and Function interface?

	Predicate	Function
1.	The predicate can return only a Boolean value.	The function can return any type of object.
2.	Predicate defined one abstract method. i.e. test() method.	The function defined one abstract method. i.e. apply() method.
3.	Public Boolean test(T t);	Public R apply(T t, R r);
4.	The predicate can take only one type of parameter which represent the input argument.	Function interface takes two parameters. The first one represents input type and the second one represent return type.
5.	Predicate<T>	Function<T,R>

    What is Consumer functional interface?

-  Consumer interface function just consumes a value, perform a certain operation and doesn’t return anything.

-    Syntax for Consumer interface is,

@FunctionalInterface public interface Consumer<T> {  }

    What is the abstract method defined in Consumer functional interface?

-          Consumer interface has only one abstract method.

-          Consumer interface has accept() method which is abstract.

-          Please refer to the below example.

@FunctionalInterface public interface Consumer<T> {     void accept(T t); }

    What are the static methods defined in Consumer functional interface?

-          There is no static method declared inside the Consumer interface.

-          Consumer interface has only one abstract method and default method.

    What is the abstract method defined in Supplier functional interface?

-          Supplier interface has defined only one abstract method.

-          Get() abstract method has defined the Supplier interface.

-          Please refer to the below syntax.

@FunctionalInterface public interface Supplier<T> {    T get(); }

    What is Bi-Consumer functional interface?

-    Bi-Consumer interface function just consumes a couple of values, perform the certain operation and doesn’t return anything.

-    Syntax for Consumer interface is,

@FunctionalInterface public interface BiConsumer<T, U> {   }

    What are the default methods defined in Consumer functional interface?

-     There is only one default method declared inside the Consumer interface.

-     The abstract method defined inside consumer is andThen().

-     Please refer to the below example.

package simplifiedjava.crackedInterview.java8;  import java.util.function.Consumer;  public class ConsumerInterfaceDemo {        public static void main(String[] args) {                        Consumer<String> c1 = s -> System.out.println("List 1 " +s);             c1.accept("Java");                        Consumer<String> c2 = s -> System.out.println("List 2 " + s);             c2.accept(".Net");             Consumer<String> c3 = c2.andThen(c1);//c2 calls first & then c1             c3.accept("Both");                  } } Output: List Item 1 Java List Item 2 .Net List Item 2 Both List Item 1 Both

1.    

    What are the static method defined in Supplier functional interface?

    -        There is no static method declared inside the Supplier interface.

    What is the difference between Predicate and Bi-Predicate?

	Predicate	Bi-Predicate
1.	Predicate accepts only one argument.	Bi-Predicate accepts two parameters.
2.	@FunctionalInterface public interface Predicate<T> {   }	@FunctionalInterface public interface BiPredicate<T, U>{   }

• Java interview questions and answers all MNC - Click here

• Basic core java interview questions and answers for freshers - Click here

• Core java interview questions for 3 years experience - Click here

• Core java interview questions and answers for 3-5 years exp - Click here

• Core java interview questions and Answers for 5 - 7 Years exp - Click here

• Basic Java Interview Questions and Answers - Click here

• Java interview questions and answers on oops - Click here

• Java interview questions and answers on Strings - Click here

• Java interview questions on exception handling - Click here

• Interview questions on multithreading in java for experienced - Click here

• Interview questions on serialization in java for experienced - Click here

• Interview questions on inner class in java for experienced - Click here

• Interview questions on Collections in java for experienced - Click here

Upcoming questions in next post:

131. What are the primitive function.

132. What is the difference between IntFunction, ToIntFunction and IntToDoubleFunction.

133. What is method Reference. How will you implements method reference.

134. Write a program to call static methods with method reference.

135. Can you call non-static method with method reference. 

136. How does it different from Collection API.

137. What are the intermidiate operations. Can you list out some intermediate operations.

138. What are the terminal operations. Can you list out some terminal operations.

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