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jamalgithubjamalgithub
committed
15/08/2018 at 14:24
1 parent 204e88b commit 5025708

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4 files changed

+155
-34
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4 files changed

+155
-34
lines changed

‎in28Munites-JavaCourse-ForBeginners/src/com/in28munites/FunctionalProgramming/FPNumberRunner.java‎

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Original file line numberDiff line numberDiff line change
@@ -2,7 +2,6 @@
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import java.util.Arrays;
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import java.util.List;
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import java.util.stream.Collectors;
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import java.util.stream.IntStream;
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public class FPNumberRunner {
@@ -26,11 +25,6 @@ public static void main(String[] args) {
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numbers.stream()
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.forEach( element ->System.out.println(element));*/
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System.out.println("Max : " + fpMaxListInt(numbers));
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System.out.println("Min : " + fpMinListInt(numbers));
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System.out.println(fpOdd(numbers));
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//int sum = normalSum(numbers);
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//int sum = fpSum(numbers);
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int sum = fpSumOdd(numbers);
@@ -60,20 +54,6 @@ private static void fpLength() {
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// .map(s -> s.length())
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// .forEach(p -> System.out.println(p.length()));
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}
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private static int fpMaxListInt(List<Integer> numbers) {
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return numbers.stream().max((n1, n2) -> Integer.compare(n1, n2)).get();
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}
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private static int fpMinListInt(List<Integer> numbers) {
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return numbers.stream().min((n1, n2) -> Integer.compare(n1, n2)).get();
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}
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private static List<Integer> fpOdd(List<Integer> numbers) {
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return numbers.stream()
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.filter(number -> number % 2 == 1)
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.collect(Collectors.toList());
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}
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private static int normalSum(List<Integer> numbers) {
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int sum = 0;

‎in28Munites-JavaCourse-ForBeginners/src/com/in28munites/FunctionalProgramming/FPNumberRunner2.java‎

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,138 @@
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package com.in28munites.FunctionalProgramming;
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import java.util.Arrays;
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import java.util.List;
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import java.util.Optional;
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import java.util.stream.Collectors;
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import java.util.stream.IntStream;
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public class FPNumberRunner2 {
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public static void main(String[] args) {
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List<Integer> numbers = Arrays.asList(4,6,8,13,3,15);
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List<Integer> numbers2 = Arrays.asList(13,3,15);
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//Exercise - Print squares of first 10 numbers!
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//Clue - IntStream.range(1,10)
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fpSquare();
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//Arrays.asList("Apple", "Ant", "Bat").stream()
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//Map all of these to lowercase and print them
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fpLowerCase();
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//List.of("Apple", "Ant", "Bat").stream()
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//Print the length of each element
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fpLength();
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/*
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numbers.stream()
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.forEach( element ->System.out.println(element));*/
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System.out.println("Max : " + fpMaxListInt(numbers));
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System.out.println("Min : " + fpMinListInt(numbers));
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System.out.println(fpOdd(numbers));
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System.out.println(fpEven(numbers));
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System.out.println(fpSquare2());
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//int sum = normalSum(numbers);
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//int sum = fpSum(numbers);
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int sum = fpSumOdd(numbers);
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//int sum = fpSumOdd2(numbers);
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System.out.println(sum);
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System.out.println(fpOptinalMaxListInt(numbers));
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System.out.println(fpOptinalMaxListInt(numbers).get());
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System.out.println(fpOptinalMaxListInt(numbers).isPresent());
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System.out.println(fpOptinalMaxListInt(numbers2));
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System.out.println(fpOptinalMaxListInt(numbers2).isPresent());
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System.out.println(fpOptinalMaxListInt(numbers2).orElse(0));
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}
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private static void fpSquare() {
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IntStream.range(1, 10)
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.map(e -> e * e)
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.forEach(p -> System.out.println(p));
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}
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private static void fpLowerCase() {
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Arrays.asList("Apple", "Ant", "Bat").stream()
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.map(s -> s.toLowerCase())
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.forEach(p -> System.out.println(p));
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}
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private static void fpLength() {
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Arrays.asList("Apple", "Ant", "Bat").stream()
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.map(s -> s.length())
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.forEach(p -> System.out.println(p));
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// Arrays.asList("Apple", "Ant", "Bat").stream()
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// .map(s -> s.length())
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// .forEach(p -> System.out.println(p.length()));
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}
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private static int fpMaxListInt(List<Integer> numbers) {
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return numbers.stream().max((n1, n2) -> Integer.compare(n1, n2)).get();
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}
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private static Optional fpOptinalMaxListInt(List<Integer> numbers) {
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return numbers.stream().filter(number -> number % 2 == 0).max((n1, n2) -> Integer.compare(n1, n2));
82+
}
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private static int fpMinListInt(List<Integer> numbers) {
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return numbers.stream().min((n1, n2) -> Integer.compare(n1, n2)).get();
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}
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private static List<Integer> fpOdd(List<Integer> numbers) {
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return numbers.stream()
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.filter(number -> number % 2 == 1)
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.collect(Collectors.toList())
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;
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}
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private static List<Integer> fpSquare2() {
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return IntStream.range(1, 11)
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.map(e -> e * e)
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.boxed()
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.collect(Collectors.toList())
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;
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}
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private static List<Integer> fpEven(List<Integer> numbers) {
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return numbers.stream()
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.filter(number -> number % 2 == 0)
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.collect(Collectors.toList());
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}
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private static int normalSum(List<Integer> numbers) {
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int sum = 0;
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for(int number:numbers) {
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sum += number;
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}
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return sum;
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}
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private static int fpSum(List<Integer> numbers) {
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return numbers.stream().reduce(0, (number1, number2) -> number1 + number2);
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}
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private static int fpSumOdd(List<Integer> numbers) {
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return numbers.stream() // Lambda Expression is a shortcut for creating a function
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.filter(number -> number % 2 == 1) // Intermediate Operation
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.reduce(0, (number1, number2) -> number1 + number2); // Terminal Operation : consume the result stream
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}
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private static int fpSumOdd2(List<Integer> numbers) {
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return numbers.stream()
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.filter(number -> number % 2 == 1)
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.reduce(0, (number1, number2) -> {
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return number1 + number2;
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}
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);
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}
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}

‎in28Munites-JavaCourse-ForBeginners/src/com/in28munites/FunctionalProgramming/LambdaBehindTheScreensRunner.java‎

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -33,20 +33,20 @@ public Integer apply(Integer number) {
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}
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public class LambdaBehindTheScreensRunner {
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public static void main(String[] args) {
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Arrays.asList(23,43,34,45,36,48).stream()
42-
.filter(n -> n%2 ==0)
43-
.map(n -> n * n)
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.forEach(e -> System.out.println(e));
40+
.filter(n -> n%2 ==0)
41+
.map(n -> n * n)
42+
.forEach(e -> System.out.println(e))
43+
;
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4645
Arrays.asList(23,43,34,45,36,48).stream()
47-
.filter(new EvenNumberPredicate())
48-
.map(new NumberSquareMapper())
49-
.forEach(new SystemOutConsumer());
46+
.filter(new EvenNumberPredicate())
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.map(new NumberSquareMapper())
48+
.forEach(new SystemOutConsumer())
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;
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5151
//.map(n -> n * n)
5252
//<R> Stream<R> map(Function<? super T, ? extends R> mapper);
@@ -65,7 +65,7 @@ public static void main(String[] args) {
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//3.Returning functions from methods
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6767
Predicate<? super Integer> evenPredicate = createEvenPredicate();
68-
Predicate<? super Integer> oddPredicate = n -> n%2 ==1;
68+
Predicate<? super Integer> oddPredicate = n -> n % 2 == 1;
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7070
Arrays.asList(23,43,34,45,36,48).stream()
7171
.filter(evenPredicate)
@@ -74,7 +74,7 @@ public static void main(String[] args) {
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}
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7676
private static Predicate<? super Integer> createEvenPredicate() {
77-
return n -> n%2 ==0;
77+
return n -> n % 2 == 0;
7878
}
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8080
}

‎in28Munites-JavaCourse-ForBeginners/src/com/in28munites/FunctionalProgramming/MethodReferencesRunner.java‎

Lines changed: 7 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -16,16 +16,19 @@ public static void main(String[] args) {
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1717
Arrays.asList("Ant", "Bat", "Cat", "Dog", "Elephant")
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.stream()
19-
.map(String::length)
20-
.forEach(MethodReferencesRunner::print);
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.map(String::length)
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// .forEach(System.out::println);
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.forEach(MethodReferencesRunner::print)
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;
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2224
Arrays.asList(23,45,67,34)
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.stream()
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.filter(n -> n%2==0)
26+
.filter(n -> n % 2 == 0)
2527
.max( (n1,n2) -> Integer.compare(n1,n2) )
2628
.orElse(0);
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28-
Integer max = Arrays.asList(23, 45, 67, 34).stream()
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Integer max = Arrays.asList(23, 45, 67, 34)
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.stream()
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.filter(MethodReferencesRunner::isEven)
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.max(Integer::compare)
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.orElse(0);

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