[BAEL-13506] - Split or move core-java-8 module (#7790)

core-java-modules/core-java-function/README.md

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+=========
+
+## Core Java 8 Cookbooks and Examples
+
+### Relevant Articles: 
+- [Java 8 Predicate Chain](https://www.baeldung.com/java-predicate-chain)

core-java-modules/core-java-function/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung</groupId>
+    <artifactId>core-java-function</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>core-java-function</name>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-java</artifactId>
+        <version>0.0.1-SNAPSHOT</version>
+        <relativePath>../../parent-java</relativePath>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <!-- test scoped -->
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>core-java-function</finalName>
+        <resources>
+            <resource>
+                <directory>src/main/resources</directory>
+                <filtering>true</filtering>
+            </resource>
+        </resources>
+    </build>
+
+    <properties>
+        <!-- testing -->
+        <assertj.version>3.6.1</assertj.version>
+        <asspectj.version>1.8.9</asspectj.version>
+        <!-- plugins -->
+        <maven-surefire-plugin.version>2.22.1</maven-surefire-plugin.version>
+    </properties>
+</project>

core-java-modules/core-java-function/src/main/resources/logback.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+    <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+        <encoder>
+            <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
+            </pattern>
+        </encoder>
+    </appender>
+
+    <root level="INFO">
+        <appender-ref ref="STDOUT" />
+    </root>
+</configuration>

core-java-modules/core-java-function/src/test/java/com/baeldung/java8/Java8PredicateChainUnitTest.java

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+package com.baeldung.java8;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.contains;
+import static org.junit.Assert.assertEquals;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.function.Predicate;
+import java.util.stream.Collectors;
+
+import org.junit.Test;
+
+public class Java8PredicateChainUnitTest {
+    
+    private List<String> names = Arrays.asList("Adam", "Alexander", "John", "Tom");
+
+    @Test
+    public void whenFilterList_thenSuccess() {
+        List<String> result = names.stream()
+            .filter(name -> name.startsWith("A"))
+            .collect(Collectors.toList());
+
+        assertEquals(2, result.size());
+        assertThat(result, contains("Adam", "Alexander"));
+    }
+
+    @Test
+    public void whenFilterListWithMultipleFilters_thenSuccess() {
+        List<String> result = names.stream()
+            .filter(name -> name.startsWith("A"))
+            .filter(name -> name.length() < 5)
+            .collect(Collectors.toList());
+        
+        assertEquals(1, result.size());
+        assertThat(result, contains("Adam"));
+    }
+
+    @Test
+    public void whenFilterListWithComplexPredicate_thenSuccess() {
+        List<String> result = names.stream()
+            .filter(name -> name.startsWith("A") && name.length() < 5)
+            .collect(Collectors.toList());
+        
+        assertEquals(1, result.size());
+        assertThat(result, contains("Adam"));
+    }
+
+    @Test
+    public void whenFilterListWithCombinedPredicatesInline_thenSuccess() {
+        List<String> result = names.stream()
+            .filter(((Predicate<String>) name -> name.startsWith("A")).and(name -> name.length() < 5))
+            .collect(Collectors.toList());
+        
+        assertEquals(1, result.size());
+        assertThat(result, contains("Adam"));
+    }
+
+    @Test
+    public void whenFilterListWithCombinedPredicatesUsingAnd_thenSuccess() {
+        Predicate<String> predicate1 = str -> str.startsWith("A");
+        Predicate<String> predicate2 = str -> str.length() < 5;
+
+        List<String> result = names.stream()
+            .filter(predicate1.and(predicate2))
+            .collect(Collectors.toList());
+
+        assertEquals(1, result.size());
+        assertThat(result, contains("Adam"));
+    }
+
+    @Test
+    public void whenFilterListWithCombinedPredicatesUsingOr_thenSuccess() {
+        Predicate<String> predicate1 = str -> str.startsWith("J");
+        Predicate<String> predicate2 = str -> str.length() < 4;
+
+        List<String> result = names.stream()
+            .filter(predicate1.or(predicate2))
+            .collect(Collectors.toList());
+
+        assertEquals(2, result.size());
+        assertThat(result, contains("John", "Tom"));
+    }
+
+    @Test
+    public void whenFilterListWithCombinedPredicatesUsingOrAndNegate_thenSuccess() {
+        Predicate<String> predicate1 = str -> str.startsWith("J");
+        Predicate<String> predicate2 = str -> str.length() < 4;
+
+        List<String> result = names.stream()
+            .filter(predicate1.or(predicate2.negate()))
+            .collect(Collectors.toList());
+
+        assertEquals(3, result.size());
+        assertThat(result, contains("Adam", "Alexander", "John"));
+    }
+
+    @Test
+    public void whenFilterListWithCollectionOfPredicatesUsingAnd_thenSuccess() {
+        List<Predicate<String>> allPredicates = new ArrayList<Predicate<String>>();
+        allPredicates.add(str -> str.startsWith("A"));
+        allPredicates.add(str -> str.contains("d"));
+        allPredicates.add(str -> str.length() > 4);
+
+        List<String> result = names.stream()
+            .filter(allPredicates.stream()
+                .reduce(x -> true, Predicate::and))
+            .collect(Collectors.toList());
+
+        assertEquals(1, result.size());
+        assertThat(result, contains("Alexander"));
+    }
+
+    @Test
+    public void whenFilterListWithCollectionOfPredicatesUsingOr_thenSuccess() {
+        List<Predicate<String>> allPredicates = new ArrayList<Predicate<String>>();
+        allPredicates.add(str -> str.startsWith("A"));
+        allPredicates.add(str -> str.contains("d"));
+        allPredicates.add(str -> str.length() > 4);
+
+        List<String> result = names.stream()
+            .filter(allPredicates.stream()
+                .reduce(x -> false, Predicate::or))
+            .collect(Collectors.toList());
+
+        assertEquals(2, result.size());
+        assertThat(result, contains("Adam", "Alexander"));
+    }
+
+}

core-java-modules/core-java-function/src/test/resources/.gitignore

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+*.class
+
+#folders#
+/target
+/neoDb*
+/data
+/src/main/webapp/WEB-INF/classes
+*/META-INF/*
+
+# Packaged files #
+*.jar
+*.war
+*.ear