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package com.code.decode; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.List; import java.util.stream.Collectors; public class Main { public static void main(String[] args) { String[] str = new String[] {"Android","Java","Dot Net","Pytthon"}; ArrayList arrayList = new ArrayList(); arrayList.add("Ruby"); Collections.addAll(arrayList,str); System.out.println(arrayList); //Using Java 8 List list = Arrays.stream(str).collect(Collectors.toList()); System.out.println(list); /*How do you increase the current capacity of an ArrayList?*/ arrayList.ensureCapacity(20); /*How do you decrease the current capacity of an ArrayList to the current size?*/ arrayList.trimToSize(); /*How do you convert an ArrayList to Array?*/ Object[] array = arrayList.toArray(); System.out.println("================================================="); //1. map(): Transforms each element in a stream. Example: Convert a list of names to uppercase. List names = List.of("John","Doe"); List upperCase = names.stream().map(String::toUpperCase).collect(Collectors.toList()); System.out.println("upper case is : "+upperCase); //2. Filter find even numbers List numbers = List.of(1,2,5,3,6,4); List evenNumbers = numbers.stream().filter(even->even%2==0).collect(Collectors.toList()); System.out.println("Eeven number is : "+evenNumbers); //3. flatMap():Flattens nested structures like lists of lists into a single stream.Example: Combine lists into one. List> listOfList = List.of(List.of(1,2,3,4),List.of(5,6,7,8,10)); List flatList = listOfList.stream().flatMap(List::stream).collect(Collectors.toList()); System.out.println(" flat list is : "+flatList); //4. reduce(): Reduces elements to a single value using an accumulator.Example: Sum a list of numbers. List listNumber = List.of(1,2,3,4,5); int sumNumber = listNumber.stream().reduce(5, Integer::sum); System.out.println("sumNumber :"+sumNumber); // } }