fix merge issue; refactoring

java-collections-maps-2/README.md

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+## Relevant Articles:
+- [Map of Primitives in Java](https://www.baeldung.com/java-map-primitives)
+- [Copying a HashMap in Java](https://www.baeldung.com/java-copy-hashmap)

java-collections-maps-2/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<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>
+    <artifactId>java-collections-maps-2</artifactId>
+    <version>0.1.0-SNAPSHOT</version>
+    <name>java-collections-maps-2</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.eclipse.collections</groupId>
+            <artifactId>eclipse-collections</artifactId>
+            <version>${eclipse-collections.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>net.sf.trove4j</groupId>
+            <artifactId>trove4j</artifactId>
+            <version>${trove4j.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>it.unimi.dsi</groupId>
+            <artifactId>fastutil</artifactId>
+            <version>${fastutil.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>colt</groupId>
+            <artifactId>colt</artifactId>
+            <version>${colt.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-lang3</artifactId>
+            <version>${commons-lang3.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <version>${assertj.version}</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <properties>
+        <eclipse-collections.version>8.2.0</eclipse-collections.version>
+        <trove4j.version>3.0.2</trove4j.version>
+        <fastutil.version>8.1.0</fastutil.version>
+        <colt.version>1.2.0</colt.version>
+        <assertj.version>3.11.1</assertj.version>
+    </properties>
+
+</project>

java-collections-maps-2/src/main/java/com/baeldung/map/CopyHashMap.java

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+package com.baeldung.map;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import org.apache.commons.lang3.SerializationUtils;
+
+public class CopyHashMap {
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingConstructor(HashMap<String, Employee> originalMap) {
+        return new HashMap<String, Employee>(originalMap);
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingClone(HashMap<String, Employee> originalMap) {
+        return (HashMap<String, Employee>) originalMap.clone();
+    }
+
+    public static <String, Employee> HashMap<String, Employee> copyUsingPut(HashMap<String, Employee> originalMap) {
+        HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
+        Set<Entry<String, Employee>> entries = originalMap.entrySet();
+        for(Map.Entry<String, Employee> mapEntry: entries) {
+            shallowCopy.put(mapEntry.getKey(), mapEntry.getValue());
+        }
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingPutAll(HashMap<String, Employee> originalMap) {
+        HashMap<String, Employee> shallowCopy = new HashMap<String, Employee>();
+        shallowCopy.putAll(originalMap);
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> copyUsingJava8Stream(HashMap<String, Employee> originalMap) {
+        Set<Entry<String, Employee>> entries = originalMap.entrySet();
+        HashMap<String, Employee> shallowCopy = (HashMap<String, Employee>) entries
+            .stream()
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
+        
+        return shallowCopy;
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> shallowCopy(HashMap<String, Employee> originalMap) {
+        return (HashMap<String, Employee>) originalMap.clone();
+    }
+    
+    public static <String, Employee> HashMap<String, Employee> deepCopy(HashMap<String, Employee> originalMap) {
+        return SerializationUtils.clone(originalMap);
+    }
+    
+}

java-collections-maps-2/src/main/java/com/baeldung/map/PrimitiveMaps.java

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+package com.baeldung.map;
+
+import cern.colt.map.AbstractIntDoubleMap;
+import cern.colt.map.OpenIntDoubleHashMap;
+import gnu.trove.map.TDoubleIntMap;
+import gnu.trove.map.hash.TDoubleIntHashMap;
+import it.unimi.dsi.fastutil.ints.Int2BooleanMap;
+import it.unimi.dsi.fastutil.ints.Int2BooleanOpenHashMap;
+import it.unimi.dsi.fastutil.ints.Int2BooleanSortedMap;
+import it.unimi.dsi.fastutil.ints.Int2BooleanSortedMaps;
+import org.eclipse.collections.api.map.primitive.ImmutableIntIntMap;
+import org.eclipse.collections.api.map.primitive.MutableIntIntMap;
+import org.eclipse.collections.api.map.primitive.MutableObjectDoubleMap;
+import org.eclipse.collections.impl.factory.primitive.IntIntMaps;
+import org.eclipse.collections.impl.factory.primitive.ObjectDoubleMaps;
+
+public class PrimitiveMaps {
+
+    public static void main(String[] args) {
+
+        eclipseCollectionsMap();
+        troveMap();
+        coltMap();
+        fastutilMap();
+    }
+
+    private static void fastutilMap() {
+        Int2BooleanMap int2BooleanMap = new Int2BooleanOpenHashMap();
+        int2BooleanMap.put(1, true);
+        int2BooleanMap.put(7, false);
+        int2BooleanMap.put(4, true);
+
+        boolean value = int2BooleanMap.get(1);
+
+        Int2BooleanSortedMap int2BooleanSorted = Int2BooleanSortedMaps.EMPTY_MAP;
+    }
+
+    private static void coltMap() {
+        AbstractIntDoubleMap map = new OpenIntDoubleHashMap();
+        map.put(1, 4.5);
+        double value = map.get(1);
+    }
+
+    private static void eclipseCollectionsMap() {
+        MutableIntIntMap mutableIntIntMap = IntIntMaps.mutable.empty();
+        mutableIntIntMap.addToValue(1, 1);
+
+        ImmutableIntIntMap immutableIntIntMap = IntIntMaps.immutable.empty();
+
+        MutableObjectDoubleMap<String> dObject = ObjectDoubleMaps.mutable.empty();
+        dObject.addToValue("price", 150.5);
+        dObject.addToValue("quality", 4.4);
+        dObject.addToValue("stability", 0.8);
+    }
+
+    private static void troveMap() {
+        double[] doubles = new double[] {1.2, 4.5, 0.3};
+        int[] ints = new int[] {1, 4, 0};
+
+        TDoubleIntMap doubleIntMap = new TDoubleIntHashMap(doubles, ints);
+
+        doubleIntMap.put(1.2, 22);
+        doubleIntMap.put(4.5, 16);
+
+        doubleIntMap.adjustValue(1.2, 1);
+        doubleIntMap.adjustValue(4.5, 4);
+        doubleIntMap.adjustValue(0.3, 7);
+    }
+}

java-collections-maps-2/src/test/java/com/baeldung/map/CopyHashMapUnitTest.java

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+package com.baeldung.map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+
+import com.google.common.collect.ImmutableMap;
+
+public class CopyHashMapUnitTest {
+    
+    @Test
+    public void givenHashMap_whenShallowCopy_thenCopyisNotSameAsOriginal() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+    
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        assertThat(shallowCopy).isNotSameAs(map);
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenShallowCopyModifyingOriginalObject_thenCopyShouldChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        
+        HashMap<String, Employee> shallowCopy = CopyHashMap.shallowCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(shallowCopy.get("emp1")).isEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenHashMap_whenDeepCopyModifyingOriginalObject_thenCopyShouldNotChange() {
+        
+        HashMap<String, Employee> map = new HashMap<>();
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        map.put("emp1",emp1);
+        map.put("emp2",emp2);
+        HashMap<String, Employee> deepCopy = CopyHashMap.deepCopy(map);
+        
+        emp1.setName("Johny");
+        
+        assertThat(deepCopy.get("emp1")).isNotEqualTo(map.get("emp1"));
+        
+    }
+    
+    @Test
+    public void givenImmutableMap_whenCopyUsingGuava_thenCopyShouldNotChange() {
+        Employee emp1 = new Employee("John");
+        Employee emp2 = new Employee("Norman");
+        
+        Map<String, Employee> map = ImmutableMap.<String, Employee> builder()
+            .put("emp1",emp1)
+            .put("emp2",emp2)
+            .build();
+        Map<String, Employee> shallowCopy = ImmutableMap.copyOf(map);
+        
+        assertThat(shallowCopy).isSameAs(map);
+        
+    }
+
+}

java-collections-maps-2/src/test/java/com/baeldung/map/Employee.java

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+package com.baeldung.map;
+
+import java.io.Serializable;
+
+public class Employee implements Serializable{
+    
+    private String name;
+    
+    public Employee(String name) {
+        super();
+        this.name = name;
+    }
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    @Override
+    public String toString() {
+        return this.name;
+    }
+ 
+}
+
+