arrays and collections

Author: vd056735

ArraysANDCollections/Demo.java

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+package org.codewithease.javatopics.ArraysANDCollections;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+public class Demo {
+
+    /*
+
+Implement a function to reverse the order of elements in an ArrayList using the Collections class.
+Write a program to find the frequency of elements in an ArrayList using the Collections class.
+Implement a function to check if two arrays are equal using the Arrays class.
+Create a method to shuffle the elements in an ArrayList using the Collections class.
+Write a program to convert an ArrayList to an array using the toArray() method.
+Implement a function to find the index of a specific element in an ArrayList using the Collections class.
+     */
+
+
+    public static void main(String[] args) {
+
+        //Write a program to find the maximum element in an array using the Arrays class.
+        int[] array = {5, 8, 3, 2, 9, 1};
+        int max = Arrays.stream(array).max().orElse(0);
+        System.out.println(max);
+
+
+        //Implement a function to remove duplicates from an ArrayList using the Collections class.
+
+        List<Integer> list = Arrays.asList(3, 5, 3, 2, 1, 5);
+        list.stream().distinct().collect(Collectors.toList()).forEach(System.out::println);
+
+
+        System.out.println("sort descending");
+        //Create a method to sort an ArrayList in descending order using the Collections class.
+
+//        list.stream().sorted(Collections.reverseOrder()).collect(Collectors.toList()).forEach(System.out::println);
+        Collections.sort(list, Collections.reverseOrder());
+        System.out.println("Sorted list in descending order: " + list);
+
+        //Write a program to find the common elements between two arrays using the Arrays class.
+
+        Integer[] array1 = {1, 2, 3, 4, 5};
+        Integer[] array2 = {4, 5, 6, 7, 8};
+        ArrayList<Integer> commonElements = new ArrayList<>(Arrays.asList(array1));
+        commonElements.retainAll(Arrays.asList(array2));
+        System.out.println("Common elements: " + commonElements);
+
+
+    }
+
+
+}
+
+