The reason we have default methods in interfaces is to allow the developers to add new methods to the interfaces without affecting the classes that implements these interfaces. Here is link for complete article. 0 solved Why can I define only default and static methods inside a java interface? [duplicate]
The big O complexity of the algorithm is O(N) where N is the array size. You cannot improve on that … for the arguments provided and producing the same output. There are some things that can be done to improve efficiency though. Hint: look for a computation that is performed on each loop iteration that … Read more
This is how you can iterate over your Map: for (Map.Entry<String, Integer> entry : killstreaks.entrySet()) { String key = entry.getKey(); Integer value = entry.getValue(); // continue here } To get a specific value (Integer) from your Map use: killstreak.get(“yourKey”); Seeing from your comment that you want to increment entries by 1, you can use: killstreaks.put(key, … Read more
List<Type> list = … list.removeIf(item -> item.getId() == something); As the name suggests, removeIf() removes all elements if they satisfy the predicate. 7 solved How to remove some items from an arraylist without loop and less time complexity?
If you just want to define a method for creating a MenuItem, then it’s easy enough: you just need to decide on the functional interface you will need for the parameter that takes the method reference (or lambda, etc). E.g. if the method signature takes no parameters and has void return type, you could use … Read more
I have adapted the java example from the wikipedia article: In this example we have different roles, each having a fixed purchasing limit and a successor. Every time a user in a role receives a purchase request that exceeds his or her limit, the request is passed to his or her successor. A builder allow … Read more
Use orElseGet: Optional<String> startingOptional = getMyOptional(); String finishingValue = startingOptional.orElseGet(() -> { System.out.println(“value not found”); return “”; }); Using .map(value -> value) is useless: transforming a value into itself doesn’t change anything. solved Is there a way to combine Java8 Optional returning a value with printing a message on null?
Use element wise comparator Compare 2 lists by compare in increasing order of index location if any non-zero value is found, return the result else compare the size of the lists sort the lists using this comparator logic Use per index comparator chain. Based on WJS’s approach Compute the maximum list size across all of … Read more
I made a working solution, please find below. public class TestClass { static ArrayList<ArrayList<Integer>> fullData = new ArrayList<>(); static ArrayList<ArrayList<Integer>> finalList = new ArrayList<>(); static int listTwocounter = 0; public static void main(String[] args) { int listOne[] = {1, 2, 3}; int listTwo[] = {7, 8, 9}; int listOneCombination = 2; int listOneSize = 3; … Read more
There are several scenarios to your question: You have enough memory to hold both the original array and a larger copy Then it’s the usual scenario, the capacity is automatically increased and you can add more elements. You have few heap memory at your disposal. In that case, you’ll get an OutOfMemoryError when ArrayList tries … Read more
I was able to solve using below solution. Now I can create multiple combinations and all are working fine. Hope somebody will find it helpful. package com.example; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.google.gson.Gson; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.stream.Collectors; public class … Read more
You can do like below: Method:1 namesList1.forEach(name -> { if (name.equalsIgnoreCase(“Kumar”)) { namesList1.set(namesList1.indexOf(name), “Singh”); } }); System.out.println(namesList1); Method :2 (Suggested by @Holger) namesList1.replaceAll(s -> s.equalsIgnoreCase(“Kumar”)? “Singh”: s); System.out.println(namesList1); 2 solved I am replacing value “Kumar” with “Singh” while Iterating ArrayList using Java 7, How it will convert using Java 8 Stream API?
abstract class ReferencePipeline<P_IN, P_OUT> extends AbstractPipeline<P_IN, P_OUT, Stream<P_OUT>> implements Stream<P_OUT> … It’s ReferencePipeline that implements them. For example: @Override public final boolean anyMatch(Predicate<? super P_OUT> predicate) { return evaluate(MatchOps.makeRef(predicate, MatchOps.MatchKind.ANY)); } 2 solved How does “Stream” in java8 work?
As a partial solution for the functions / methods (if they don’t need arguments) you can use Threads or an ExecutorService and method references. If you need arguments you will have to write lambda expressions – see the method t3 and it’s start for an example. public class Test { public void t1() { System.out.println(“t1”); … Read more
Files#lines returns a stream of all the lines in the file. You could join these lines to a single string, and then split it according to the separator: String separator = “:”; // for example… String entireFile = Files.lines(Paths.get(“file.txt”)).collect(Collectors.joining()); String[] separated = entireFile.split(separator); solved How to read txt file and save as a single string … Read more