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amdegregorioamdegregorio
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BAEL-4925 (eugenp#10746)
* BAEL-4925 * BAEL-4925
1 parent 92d4fd0 commit 69b8522

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‎core-java-modules/core-java-lang-4/src/main/java/com/baeldung/hash/Player.java‎

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package com.baeldung.hash;
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import java.util.Objects;
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public class Player {
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private String firstName;
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private String lastName;
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private String position;
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public Player() {
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}
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public Player(String firstName, String lastName, String position) {
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this.firstName = firstName;
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this.lastName = lastName;
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this.position = position;
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}
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public String getFirstName() {
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return firstName;
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}
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public void setFirstName(String firstName) {
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this.firstName = firstName;
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}
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public String getLastName() {
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return lastName;
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}
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public void setLastName(String lastName) {
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this.lastName = lastName;
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}
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public String getPosition() {
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return position;
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}
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public void setPosition(String position) {
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this.position = position;
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}
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@Override
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public int hashCode() {
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return Objects.hash(firstName, lastName, position);
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}
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@Override
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public boolean equals(Object obj) {
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if (this == obj) {
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return true;
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}
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if (obj == null) {
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return false;
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}
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if (getClass() != obj.getClass()) {
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return false;
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}
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Player other = (Player) obj;
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if (firstName == null) {
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if (other.firstName != null) {
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return false;
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}
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} else if (!firstName.equals(other.firstName)) {
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return false;
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}
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if (lastName == null) {
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if (other.lastName != null) {
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return false;
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}
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} else if (!lastName.equals(other.lastName)) {
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return false;
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}
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if (position == null) {
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if (other.position != null) {
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return false;
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}
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} else if (!position.equals(other.position)) {
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return false;
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}
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return true;
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}
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}

‎core-java-modules/core-java-lang-4/src/test/java/com/baeldung/hash/HashCodeUnitTest.java‎

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package com.baeldung.hash;
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import static org.junit.Assert.assertEquals;
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import static org.junit.Assert.assertNotEquals;
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import java.util.Objects;
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import org.junit.Test;
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public class HashCodeUnitTest {
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@Test
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public void whenCallingObjectsHashCodeOnIndenticalObjects_thenSameHashCodeReturned() {
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String stringOne = "test";
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String stringTwo = "test";
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int hashCode1 = Objects.hashCode(stringOne);
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int hashCode2 = Objects.hashCode(stringTwo);
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assertEquals(hashCode1, hashCode2);
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}
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@Test
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public void whenCallingObjectsHashCodeOnNullObject_thenZeroReturned() {
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String nullString = null;
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int hashCode = Objects.hashCode(nullString);
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assertEquals(0, hashCode);
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}
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@Test
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public void whenCallingObjectHashCodeOnIndenticalObjects_thenSameHashCodeReturned() {
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Double valueOne = Double.valueOf(1.0012);
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Double valueTwo = Double.valueOf(1.0012);
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int hashCode1 = valueOne.hashCode();
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int hashCode2 = valueTwo.hashCode();
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assertEquals(hashCode1, hashCode2);
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}
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@Test(expected = NullPointerException.class)
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public void whenCallingObjectHashCodeOnNullObject_theNullPointerExceptionThrown() {
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Double value = null;
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value.hashCode();
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}
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@Test
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public void whenCallingObjectsHashOnStrings_thenSameHashCodeReturned() {
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String strOne = "one";
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String strTwo = "two";
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String strOne2 = "one";
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String strTwo2 = "two";
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int hashCode1 = Objects.hash(strOne, strTwo);
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int hashCode2 = Objects.hash(strOne2, strTwo2);
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assertEquals(hashCode1, hashCode2);
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}
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@Test
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public void whenCallingObjectsHashOnSingleString_thenDifferentHashcodeFromObjectsHashCodeCallReturned() {
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String testString = "test string";
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int hashCode1 = Objects.hash(testString);
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int hashCode2 = Objects.hashCode(testString);
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assertNotEquals(hashCode1, hashCode2);
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}
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}

‎core-java-modules/core-java-lang-4/src/test/java/com/baeldung/hash/PlayerUnitTest.java‎

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package com.baeldung.hash;
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import static org.junit.Assert.assertEquals;
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import java.util.Arrays;
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import org.junit.Test;
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public class PlayerUnitTest {
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@Test
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public void whenCallingHashCodeOnIdenticalValue_thenSameHashCodeReturned() {
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Player player = new Player("Eduardo", "Rodriguez", "Pitcher");
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Player indenticalPlayer = new Player("Eduardo", "Rodriguez", "Pitcher");
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int hashCode1 = player.hashCode();
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int hashCode2 = player.hashCode();
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int hashCode3 = indenticalPlayer.hashCode();
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assertEquals(hashCode1, hashCode2);
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assertEquals(hashCode1, hashCode3);
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}
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@Test
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public void whenCallingHashCodeAndArraysHashCode_thenSameHashCodeReturned() {
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Player player = new Player("Bobby", "Dalbec", "First Base");
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int hashcode1 = player.hashCode();
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String[] playerInfo = { "Bobby", "Dalbec", "First Base" };
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int hashcode2 = Arrays.hashCode(playerInfo);
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assertEquals(hashcode1, hashcode2);
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}
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}

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