Merge pull request #38 from amitrp/aph-15293_compare_java_lists

aph-15293 compare two lists

Author: amitrp

README.md

@@ -117,6 +117,9 @@ This project contains Core Java code samples that are used as examples on [amitp
 
 ### [Finding the Differences Between Two Java Lists](https://www.amitph.com/java-find-lists-difference/)
 
+### [Comparing Two Lists In Java](https://www.amitph.com/java-compare-lists/)
+
+
 ## How to use
 *Clone the project using*
 ```

java-collections/README.md

@@ -80,6 +80,8 @@ This project contains Java Collections code samples that are used as examples on
 
 ### [Finding the Differences Between Two Java Lists](https://www.amitph.com/java-find-lists-difference/)
 
+### [Comparing Two Lists In Java](https://www.amitph.com/java-compare-lists/)
+
 ## How to use
 *Clone the project using*
 ```

java-collections/src/main/java/com/amitph/java/collections/list/ListsComparer.java

@@ -0,0 +1,65 @@
+package com.amitph.java.collections.list;
+
+import org.apache.commons.collections4.CollectionUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Predicate;
+
+public class ListsComparer {
+    public void checkEquality() {
+        List<Integer> one = List.of(1, 2, 4, 6, 8);
+        List<Integer> two = List.of(1, 2, 4, 6, 8);
+        List<Integer> three = List.of(1, 2, 4, 6, 8, 4);
+
+        System.out.println(one.equals(two));
+        System.out.println(one.equals(three));
+    }
+
+    public void findCommonElements() {
+        List<Integer> one = List.of(1, 2, 4, 6, 8);
+        List<Integer> two = List.of(3, 4, 5, 6, 7);
+
+        //Plain Java
+        List<Integer> commons = new ArrayList<>(one);
+        commons.retainAll(two);
+        System.out.println(commons);
+
+        //Java Streams
+        commons = one.stream()
+                .filter(two::contains)
+                .toList();
+        System.out.println(commons);
+
+        //Apache Commons Collections
+        commons = new ArrayList<>(CollectionUtils.intersection(one, two));
+        System.out.println(commons);
+    }
+
+    public void findDifferentElements() {
+        List<Integer> one = List.of(1, 2, 4, 6, 8);
+        List<Integer> two = List.of(3, 4, 5, 6, 7);
+
+        //Plain Java
+        List<Integer> difference = new ArrayList<>(one);
+        difference.removeAll(two);
+        System.out.println(difference);
+
+        //Java Streams
+        difference = one.stream()
+                .filter(Predicate.not(two::contains))
+                .toList();
+        System.out.println(difference);
+
+        //Apache Commons Collections
+        difference = new ArrayList<>(CollectionUtils.removeAll(one, two));
+        System.out.println(difference);
+    }
+
+    public static void main(String[] a) {
+        ListsComparer comparer = new ListsComparer();
+        comparer.checkEquality();
+        comparer.findCommonElements();
+        comparer.findDifferentElements();
+    }
+}