Java Stream why does reduce requires two parameters of the functional Interface?

In other words, why does reduce require BinaryOperator, or BiFunction interface? Why doesn’t it use UnaryOperator, or Function interface instead? What is the point of having two parameters as the …

MapReduce filtering to get customers not in order list?

Currently learning on MapReduce and trying to figure out how to code this into Java. Two input files, called customers.txt and car_orders.txt: customers.txt =================== 12345 Peter 12346 …

Java Hashmap – Please explain how hash maps work

I am currently preparing for interviews, Java in particular. A common question is to explain hash maps. Every explanation says that in case there is more than a single value per key, the values are …

java.lang.ClassCastException exception using ObjectInputStream, when sending a class as an object

https://github.com/IshayKom/RCProject Classes As Shown in the eclipse package manager (I don’t really deal with github so I don’t know how to upload classes correctly) I got an error running my …

i’m searching for a way to improve this function that’s basically doing the control of double input data type

this is my Function to control the double input from the user but it control only integer values if the user enter a comma ‘,’ character like for example 100,300 it refuse to accept it so i’m thinking …

How to solve Cannot invoke “String.compareTo(String)” because “[]” is null?

import java.util.Scanner; public class Search { static Scanner scanner = new Scanner(System.in); static Scanner kb = new Scanner(System.in); static Scanner kb2 = new Scanner(System.in); …

Java Iterator in C++

I am a Java user and I am getting into C++ and in Java it allows classes to reveal Iterable types so clients can traverse some instance’s collection of data. Is there any way to obtain this …

HTML5 video skips ranges after 32,768

I am exploring Http Range requests and video streaming with Java. I wanted to create a controller which streams a video to a tag. For some reason, after end range of 32768, the browser sends request …

parallel() not work with the 3-arg iterate()

Here is my code: int count=20; Stream.iterate(4,i->ii+1).parallel().forEach(i -> { try { Thread.sleep(new Random().nextInt(2000)); } catch (InterruptedException …

Is Android AsyncTask use multithreading because android official web says?

while learning the difference between multi-threading and Concurrency.i follow this stackoverflow answer according to my understanding AsyncTask is just used to on or off the use of main thread{ui …