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Merge remote-tracking branch 'upstream/master' into feature/BAEL-6695-BooleanValidation

This commit is contained in:
Niket Agrawal 2023-10-14 21:24:01 +05:30
parent 78d0fa3656 24dcde3d6d
commit 8999b501c9
198 changed files with 3200 additions and 640 deletions
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102
algorithms-modules/algorithms-miscellaneous-7/src/main/java/com/baeldung/algorithms/rotatearray/RotateArray.java Normal file
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@ -0,0 +1,102 @@
package com.baeldung.algorithms.rotatearray;
/**
* To speed up the rotation, we narrow k rotations to the remainder of k divided by the array length, or k module the array length.
* Therefore, a large rotation number will be translated into the relative smallest rotation.
* All solutions replace the original array, although they might use an extra array to compute the rotation.
*/
public class RotateArray {
private RotateArray() {
throw new IllegalStateException("Rotate array algorithm utility methods class");
}
/**
*
* @param arr array to apply rotation to
* @param k number of rotations
*/
public static void bruteForce(int[] arr, int k) {
checkInvalidInput(arr, k);
k %= arr.length;
int temp;
int previous;
for (int i = 0; i < k; i++) {
previous = arr[arr.length - 1];
for (int j = 0; j < arr.length; j++) {
temp = arr[j];
arr[j] = previous;
previous = temp;
}
}
}
/**
*
* @param arr array to apply rotation to
* @param k number of rotations
*/
public static void withExtraArray(int[] arr, int k) {
checkInvalidInput(arr, k);
int[] extraArray = new int[arr.length];
for (int i = 0; i < arr.length; i++) {
extraArray[(i + k) % arr.length] = arr[i];
}
System.arraycopy(extraArray, 0, arr, 0, arr.length);
}
/**
*
* @param arr array to apply rotation to
* @param k number of rotations
*/
public static void cyclicReplacement(int[] arr, int k) {
checkInvalidInput(arr, k);
k = k % arr.length;
int count = 0;
for (int start = 0; count < arr.length; start++) {
int current = start;
int prev = arr[start];
do {
int next = (current + k) % arr.length;
int temp = arr[next];
arr[next] = prev;
prev = temp;
current = next;
count++;
} while (start != current);
}
}
/**
*
* @param arr array to apply rotation to
* @param k number of rotations
*/
public static void reverse(int[] arr, int k) {
checkInvalidInput(arr, k);
k %= arr.length;
reverse(arr, 0, arr.length - 1);
reverse(arr, 0, k - 1);
reverse(arr, k, arr.length - 1);
}
private static void reverse(int[] nums, int start, int end) {
while (start < end) {
int temp = nums[start];
nums[start] = nums[end];
nums[end] = temp;
start++;
end--;
}
}
private static void checkInvalidInput(int[] arr, int rotation) {
if (rotation < 1 || arr == null)
throw new IllegalArgumentException("Rotation must be greater than zero or array must be not null");
}
}

124
algorithms-modules/algorithms-miscellaneous-7/src/test/java/com/baeldung/algorithms/rotatearray/RotateArrayUnitTest.java Normal file
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@ -0,0 +1,124 @@
package com.baeldung.algorithms.rotatearray;
import static com.baeldung.algorithms.rotatearray.RotateArray.bruteForce;
import static com.baeldung.algorithms.rotatearray.RotateArray.cyclicReplacement;
import static com.baeldung.algorithms.rotatearray.RotateArray.reverse;
import static com.baeldung.algorithms.rotatearray.RotateArray.withExtraArray;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import org.junit.jupiter.api.Test;
class RotateArrayUnitTest {
private final int[] arr = { 1, 2, 3, 4, 5, 6 };
private final int rotationLtArrayLength = 1;
private final int rotationGtArrayLength = arr.length + 2;
private final int[] ltArrayLengthRotation = { 6, 1, 2, 3, 4, 5 };
private final int[] gtArrayLengthRotation = { 5, 6, 1, 2, 3, 4 };
@Test
void givenInputArray_whenNoRotationOrEmptyArray_thenThrowIllegalArgumentException() {
final int noRotation = 0;
final int someRotation = arr.length - 1;
assertThrows(IllegalArgumentException.class, () -> bruteForce(arr, noRotation));
assertThrows(IllegalArgumentException.class, () -> withExtraArray(arr, noRotation));
assertThrows(IllegalArgumentException.class, () -> cyclicReplacement(arr, noRotation));
assertThrows(IllegalArgumentException.class, () -> reverse(arr, noRotation));
assertThrows(IllegalArgumentException.class, () -> bruteForce(null, someRotation));
assertThrows(IllegalArgumentException.class, () -> withExtraArray(null, someRotation));
assertThrows(IllegalArgumentException.class, () -> cyclicReplacement(null, someRotation));
assertThrows(IllegalArgumentException.class, () -> reverse(null, someRotation));
}
@Test
void givenInputArray_whenUseBruteForceRotationLtArrayLength_thenRotateArrayOk() {
bruteForce(arr, rotationLtArrayLength);
assertArrayEquals(ltArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseBruteForceRotationGtArrayLength_thenRotateArrayOk() {
bruteForce(arr, rotationGtArrayLength);
assertArrayEquals(gtArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseBruteForceRotationEqArrayLength_thenDoNothing() {
int[] expected = arr.clone();
bruteForce(arr, arr.length);
assertArrayEquals(expected, arr);
}
@Test
void givenInputArray_whenUseExtraArrayRotationLtArrayLength_thenRotateArrayOk() {
withExtraArray(arr, rotationLtArrayLength);
assertArrayEquals(ltArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseExtraArrayRotationGtArrayLength_thenRotateArrayOk() {
withExtraArray(arr, rotationGtArrayLength);
assertArrayEquals(gtArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseExtraArrayWithRotationEqArrayLength_thenDoNothing() {
int[] clone = arr.clone();
withExtraArray(arr, arr.length);
assertArrayEquals(clone, arr);
}
@Test
void givenInputArray_whenUseCyclicReplacementRotationLtArrayLength_thenRotateArrayOk() {
cyclicReplacement(arr, rotationLtArrayLength);
assertArrayEquals(ltArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseCyclicReplacementRotationGtArrayLength_thenRotateArrayOk() {
cyclicReplacement(arr, rotationGtArrayLength);
assertArrayEquals(gtArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseCyclicReplacementRotationEqArrayLength_thenDoNothing() {
int[] clone = arr.clone();
cyclicReplacement(arr, arr.length);
assertArrayEquals(clone, arr);
}
@Test
void givenInputArray_whenUseReverseRotationLtArrayLength_thenRotateArrayOk() {
reverse(arr, rotationLtArrayLength);
assertArrayEquals(ltArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseReverseRotationGtArrayLength_thenRotateArrayOk() {
reverse(arr, rotationGtArrayLength);
assertArrayEquals(gtArrayLengthRotation, arr);
}
@Test
void givenInputArray_whenUseReverseRotationEqArrayLength_thenDoNothing() {
int[] clone = arr.clone();
reverse(arr, arr.length);
assertArrayEquals(clone, arr);
}
}

2
aws-modules/aws-dynamodb/.gitignore vendored Normal file
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@ -0,0 +1,2 @@
/target/
.idea/

7
aws-modules/aws-dynamodb/README.md Normal file
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@ -0,0 +1,7 @@
## AWS DYNAMODB
This module contains articles about AWS DynamoDB
### Relevant articles
- [Integration Testing with a Local DynamoDB Instance](https://www.baeldung.com/dynamodb-local-integration-tests)

87
aws-modules/aws-dynamodb/pom.xml Normal file
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@ -0,0 +1,87 @@
<?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>aws-dynamodb</artifactId>
<version>0.1.0-SNAPSHOT</version>
<name>aws-dynamodb</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>aws-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk</artifactId>
<version>${aws-java-sdk.version}</version>
</dependency>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>DynamoDBLocal</artifactId>
<version>${dynamodblocal.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>${commons-io.version}</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>${gson.version}</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-shade-plugin</artifactId>
<version>${maven-shade-plugin.version}</version>
<configuration>
<createDependencyReducedPom>false</createDependencyReducedPom>
</configuration>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>shade</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>${maven-plugins-version}</version>
<executions>
<execution>
<id>copy</id>
<phase>compile</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<includeScope></includeScope>
<includeTypes>so,dll,dylib</includeTypes>
<outputDirectory>native-libs</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<properties>
<gson.version>2.8.0</gson.version>
<dynamodblocal.version>1.21.1</dynamodblocal.version>
<maven-plugins-version>3.1.1</maven-plugins-version>
</properties>
</project>

0
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/dynamodb/entity/ProductInfo.java → aws-modules/aws-dynamodb/src/main/java/com/baeldung/dynamodb/entity/ProductInfo.java
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0
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/dynamodb/repository/AbstractRepository.java → aws-modules/aws-dynamodb/src/main/java/com/baeldung/dynamodb/repository/AbstractRepository.java
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0
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/dynamodb/repository/ProductInfoRepository.java → aws-modules/aws-dynamodb/src/main/java/com/baeldung/dynamodb/repository/ProductInfoRepository.java
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13
aws-modules/aws-dynamodb/src/main/resources/logback.xml Normal file
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@ -0,0 +1,13 @@
<?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>

8
aws-modules/aws-miscellaneous/src/test/java/com/baeldung/dynamodb/ProductInfoRepositoryIntegrationTest.java → aws-modules/aws-dynamodb/src/test/java/com/baeldung/dynamodb/ProductInfoRepositoryIntegrationTest.java
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@ -49,10 +49,10 @@ public class ProductInfoRepositoryIntegrationTest {
@BeforeClass
public static void setupClass() {
Properties testProperties = loadFromFileInClasspath("test.properties")
.filter(properties -> !isEmpty(properties.getProperty(AWS_ACCESSKEY)))
.filter(properties -> !isEmpty(properties.getProperty(AWS_SECRETKEY)))
.filter(properties -> !isEmpty(properties.getProperty(DYNAMODB_ENDPOINT)))
.orElseThrow(() -> new RuntimeException("Unable to get all of the required test property values"));
.filter(properties -> !isEmpty(properties.getProperty(AWS_ACCESSKEY)))
.filter(properties -> !isEmpty(properties.getProperty(AWS_SECRETKEY)))
.filter(properties -> !isEmpty(properties.getProperty(DYNAMODB_ENDPOINT)))
.orElseThrow(() -> new RuntimeException("Unable to get all of the required test property values"));
String amazonAWSAccessKey = testProperties.getProperty(AWS_ACCESSKEY);
String amazonAWSSecretKey = testProperties.getProperty(AWS_SECRETKEY);

0
aws-modules/aws-miscellaneous/src/test/java/com/baeldung/dynamodb/rule/LocalDbCreationRule.java → aws-modules/aws-dynamodb/src/test/java/com/baeldung/dynamodb/rule/LocalDbCreationRule.java
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0
aws-modules/aws-miscellaneous/src/test/resources/test.properties → aws-modules/aws-dynamodb/src/test/resources/test.properties
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36
aws-modules/aws-miscellaneous/pom.xml
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@ -16,31 +16,9 @@
<dependencies>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk</artifactId>
<version>${aws-java-sdk.version}</version>
</dependency>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-lambda-java-core</artifactId>
<version>${aws-lambda-java-core.version}</version>
<exclusions>
<exclusion>
<artifactId>commons-logging</artifactId>
<groupId>commons-logging</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-lambda-java-events</artifactId>
<version>${aws-lambda-java-events.version}</version>
<exclusions>
<exclusion>
<artifactId>commons-logging</artifactId>
<groupId>commons-logging</groupId>
</exclusion>
</exclusions>
<groupId>software.amazon.awssdk</groupId>
<artifactId>aws-sdk-java</artifactId>
<version>${aws-java-sdk-v2.version}</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
@ -52,12 +30,6 @@
<artifactId>gson</artifactId>
<version>${gson.version}</version>
</dependency>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>DynamoDBLocal</artifactId>
<version>${dynamodblocal.version}</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
@ -101,8 +73,6 @@
</build>
<properties>
<aws-lambda-java-events.version>1.3.0</aws-lambda-java-events.version>
<aws-lambda-java-core.version>1.1.0</aws-lambda-java-core.version>
<gson.version>2.8.0</gson.version>
<dynamodblocal.version>1.21.1</dynamodblocal.version>
<commons-codec-version>1.10.L001</commons-codec-version>

180
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/ec2/EC2Application.java
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@ -2,136 +2,148 @@ package com.baeldung.ec2;
import java.util.Arrays;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.ec2.AmazonEC2;
import com.amazonaws.services.ec2.AmazonEC2ClientBuilder;
import com.amazonaws.services.ec2.model.AuthorizeSecurityGroupIngressRequest;
import com.amazonaws.services.ec2.model.CreateKeyPairRequest;
import com.amazonaws.services.ec2.model.CreateKeyPairResult;
import com.amazonaws.services.ec2.model.CreateSecurityGroupRequest;
import com.amazonaws.services.ec2.model.DescribeInstancesRequest;
import com.amazonaws.services.ec2.model.DescribeInstancesResult;
import com.amazonaws.services.ec2.model.DescribeKeyPairsRequest;
import com.amazonaws.services.ec2.model.DescribeKeyPairsResult;
import com.amazonaws.services.ec2.model.IpPermission;
import com.amazonaws.services.ec2.model.IpRange;
import com.amazonaws.services.ec2.model.MonitorInstancesRequest;
import com.amazonaws.services.ec2.model.RebootInstancesRequest;
import com.amazonaws.services.ec2.model.RunInstancesRequest;
import com.amazonaws.services.ec2.model.StartInstancesRequest;
import com.amazonaws.services.ec2.model.StopInstancesRequest;
import com.amazonaws.services.ec2.model.UnmonitorInstancesRequest;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.ec2.Ec2Client;
import software.amazon.awssdk.services.ec2.model.AuthorizeSecurityGroupIngressRequest;
import software.amazon.awssdk.services.ec2.model.CreateKeyPairRequest;
import software.amazon.awssdk.services.ec2.model.CreateKeyPairResponse;
import software.amazon.awssdk.services.ec2.model.CreateSecurityGroupRequest;
import software.amazon.awssdk.services.ec2.model.DescribeInstancesRequest;
import software.amazon.awssdk.services.ec2.model.DescribeInstancesResponse;
import software.amazon.awssdk.services.ec2.model.DescribeKeyPairsRequest;
import software.amazon.awssdk.services.ec2.model.DescribeKeyPairsResponse;
import software.amazon.awssdk.services.ec2.model.IpPermission;
import software.amazon.awssdk.services.ec2.model.IpRange;
import software.amazon.awssdk.services.ec2.model.MonitorInstancesRequest;
import software.amazon.awssdk.services.ec2.model.RebootInstancesRequest;
import software.amazon.awssdk.services.ec2.model.RunInstancesRequest;
import software.amazon.awssdk.services.ec2.model.RunInstancesResponse;
import software.amazon.awssdk.services.ec2.model.StartInstancesRequest;
import software.amazon.awssdk.services.ec2.model.StartInstancesResponse;
import software.amazon.awssdk.services.ec2.model.StopInstancesRequest;
import software.amazon.awssdk.services.ec2.model.UnmonitorInstancesRequest;
public class EC2Application {
private static final AWSCredentials credentials;
static {
// put your accesskey and secretkey here
credentials = new BasicAWSCredentials(
"<AWS accesskey>",
"<AWS secretkey>"
);
}
public static void main(String[] args) {
// Set up the client
AmazonEC2 ec2Client = AmazonEC2ClientBuilder.standard()
.withCredentials(new AWSStaticCredentialsProvider(credentials))
.withRegion(Regions.US_EAST_1)
Ec2Client ec2Client = Ec2Client.builder()
.credentialsProvider(ProfileCredentialsProvider.create("default"))
.region(Region.US_EAST_1)
.build();
// Create a security group
CreateSecurityGroupRequest createSecurityGroupRequest = new CreateSecurityGroupRequest().withGroupName("BaeldungSecurityGroup")
.withDescription("Baeldung Security Group");
CreateSecurityGroupRequest createSecurityGroupRequest = CreateSecurityGroupRequest.builder()
.groupName("BaeldungSecurityGroup")
.description("Baeldung Security Group")
.build();
ec2Client.createSecurityGroup(createSecurityGroupRequest);
// Allow HTTP and SSH traffic
IpRange ipRange1 = new IpRange().withCidrIp("0.0.0.0/0");
IpRange ipRange1 = IpRange.builder()
.cidrIp("0.0.0.0/0")
.build();
IpPermission ipPermission1 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
.withIpProtocol("tcp")
.withFromPort(80)
.withToPort(80);
IpPermission ipPermission1 = IpPermission.builder()
.ipRanges(Arrays.asList(ipRange1))
.ipProtocol("tcp")
.fromPort(80)
.toPort(80)
.build();
IpPermission ipPermission2 = new IpPermission().withIpv4Ranges(Arrays.asList(new IpRange[] { ipRange1 }))
.withIpProtocol("tcp")
.withFromPort(22)
.withToPort(22);
IpPermission ipPermission2 = IpPermission.builder()
.ipRanges(Arrays.asList(ipRange1))
.ipProtocol("tcp")
.fromPort(22)
.toPort(22)
.build();
AuthorizeSecurityGroupIngressRequest authorizeSecurityGroupIngressRequest = new AuthorizeSecurityGroupIngressRequest()
.withGroupName("BaeldungSecurityGroup")
.withIpPermissions(ipPermission1, ipPermission2);
AuthorizeSecurityGroupIngressRequest authorizeSecurityGroupIngressRequest = AuthorizeSecurityGroupIngressRequest
.builder()
.groupName("BaeldungSecurityGroup")
.ipPermissions(ipPermission1, ipPermission2)
.build();
ec2Client.authorizeSecurityGroupIngress(authorizeSecurityGroupIngressRequest);
// Create KeyPair
CreateKeyPairRequest createKeyPairRequest = new CreateKeyPairRequest()
.withKeyName("baeldung-key-pair");
CreateKeyPairResult createKeyPairResult = ec2Client.createKeyPair(createKeyPairRequest);
String privateKey = createKeyPairResult
.getKeyPair()
.getKeyMaterial(); // make sure you keep it, the private key, Amazon doesn't store the private key
CreateKeyPairRequest createKeyPairRequest = CreateKeyPairRequest.builder()
.keyName("baeldung-key-pair")
.build();
CreateKeyPairResponse createKeyPairResponse = ec2Client.createKeyPair(createKeyPairRequest);
String privateKey = createKeyPairResponse.keyMaterial();
// make sure you keep it, the private key, Amazon doesn't store the private key
// See what key-pairs you've got
DescribeKeyPairsRequest describeKeyPairsRequest = new DescribeKeyPairsRequest();
DescribeKeyPairsResult describeKeyPairsResult = ec2Client.describeKeyPairs(describeKeyPairsRequest);
DescribeKeyPairsRequest describeKeyPairsRequest = DescribeKeyPairsRequest.builder()
.build();
DescribeKeyPairsResponse describeKeyPairsResponse = ec2Client.describeKeyPairs(describeKeyPairsRequest);
// Launch an Amazon Instance
RunInstancesRequest runInstancesRequest = new RunInstancesRequest().withImageId("ami-97785bed") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AMIs.html | https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/usingsharedamis-finding.html
.withInstanceType("t2.micro") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html
.withMinCount(1)
.withMaxCount(1)
.withKeyName("baeldung-key-pair") // optional - if not present, can't connect to instance
.withSecurityGroups("BaeldungSecurityGroup");
RunInstancesRequest runInstancesRequest = RunInstancesRequest.builder()
.imageId("ami-97785bed")
.instanceType("t2.micro") // https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html
.minCount(1)
.maxCount(1)
.keyName("baeldung-key-pair") // optional - if not present, can't connect to instance
.securityGroups("BaeldungSecurityGroup")
.build();
String yourInstanceId = ec2Client.runInstances(runInstancesRequest).getReservation().getInstances().get(0).getInstanceId();
RunInstancesResponse runInstancesResponse = ec2Client.runInstances(runInstancesRequest);
String yourInstanceId = runInstancesResponse.instances().get(0).instanceId();
// Start an Instance
StartInstancesRequest startInstancesRequest = new StartInstancesRequest()
.withInstanceIds(yourInstanceId);
StartInstancesRequest startInstancesRequest = StartInstancesRequest.builder()
.instanceIds(yourInstanceId)
.build();
StartInstancesResponse startInstancesResponse = ec2Client.startInstances(startInstancesRequest);
ec2Client.startInstances(startInstancesRequest);
// Monitor Instances
MonitorInstancesRequest monitorInstancesRequest = new MonitorInstancesRequest()
.withInstanceIds(yourInstanceId);
MonitorInstancesRequest monitorInstancesRequest = MonitorInstancesRequest.builder()
.instanceIds(yourInstanceId)
.build();
ec2Client.monitorInstances(monitorInstancesRequest);
UnmonitorInstancesRequest unmonitorInstancesRequest = new UnmonitorInstancesRequest()
.withInstanceIds(yourInstanceId);
UnmonitorInstancesRequest unmonitorInstancesRequest = UnmonitorInstancesRequest.builder()
.instanceIds(yourInstanceId)
.build();
ec2Client.unmonitorInstances(unmonitorInstancesRequest);
// Reboot an Instance
RebootInstancesRequest rebootInstancesRequest = new RebootInstancesRequest()
.withInstanceIds(yourInstanceId);
RebootInstancesRequest rebootInstancesRequest = RebootInstancesRequest.builder()
.instanceIds(yourInstanceId)
.build();
ec2Client.rebootInstances(rebootInstancesRequest);
// Stop an Instance
StopInstancesRequest stopInstancesRequest = new StopInstancesRequest()
.withInstanceIds(yourInstanceId);
StopInstancesRequest stopInstancesRequest = StopInstancesRequest.builder()
.instanceIds(yourInstanceId)
.build();
ec2Client.stopInstances(stopInstancesRequest)
.getStoppingInstances()
.stoppingInstances()
.get(0)
.getPreviousState()
.getName();
.previousState()
.name();
// Describe an Instance
DescribeInstancesRequest describeInstancesRequest = new DescribeInstancesRequest();
DescribeInstancesResult response = ec2Client.describeInstances(describeInstancesRequest);
System.out.println(response.getReservations()
DescribeInstancesRequest describeInstancesRequest = DescribeInstancesRequest.builder().build();
DescribeInstancesResponse response = ec2Client.describeInstances(describeInstancesRequest);
System.out.println(response.reservations()
.get(0)
.getInstances()
.instances()
.get(0)
.getKernelId());
.kernelId());
}
}

107
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/rds/AWSRDSService.java
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@ -1,13 +1,5 @@
package com.baeldung.rds;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.rds.AmazonRDS;
import com.amazonaws.services.rds.AmazonRDSClientBuilder;
import com.amazonaws.services.rds.model.*;
import java.io.IOException;
import java.io.InputStream;
import java.sql.*;
@ -16,12 +8,22 @@ import java.util.Properties;
import java.util.UUID;
import java.util.logging.Logger;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.rds.RdsClient;
import software.amazon.awssdk.services.rds.model.CreateDbInstanceRequest;
import software.amazon.awssdk.services.rds.model.CreateDbInstanceResponse;
import software.amazon.awssdk.services.rds.model.DBInstance;
import software.amazon.awssdk.services.rds.model.DeleteDbInstanceRequest;
import software.amazon.awssdk.services.rds.model.DeleteDbInstanceResponse;
import software.amazon.awssdk.services.rds.model.DescribeDbInstancesResponse;
import software.amazon.awssdk.services.rds.model.Endpoint;
public class AWSRDSService {
final static Logger logger = Logger.getLogger(AWSRDSService.class.getName());
private AWSCredentialsProvider credentials;
private AmazonRDS amazonRDS;
private RdsClient rdsClient;
private String db_username;
private String db_password;
private String db_database;
@ -34,22 +36,17 @@ public class AWSRDSService {
* **/
public AWSRDSService() throws IOException {
//Init RDS client with credentials and region.
credentials = new
AWSStaticCredentialsProvider(new
BasicAWSCredentials("<ACCESS_KEY>",
"<SECRET_KEY>"));
amazonRDS = AmazonRDSClientBuilder.standard().withCredentials(credentials)
.withRegion(Regions.AP_SOUTHEAST_2).build();
Properties prop = new Properties();
InputStream input = AWSRDSService.class.getClassLoader().getResourceAsStream("db.properties");
prop.load(input);
db_username = prop.getProperty("db_username");
db_password = prop.getProperty("db_password");
db_database = prop.getProperty("db_database");
}
public AWSRDSService(AmazonRDS amazonRDS){
this.amazonRDS = amazonRDS;
rdsClient = RdsClient.builder()
.region(Region.AP_SOUTHEAST_2)
.credentialsProvider(ProfileCredentialsProvider.create("default"))
.build();
}
/**
@ -60,29 +57,29 @@ public class AWSRDSService {
public String launchInstance() {
String identifier = "";
CreateDBInstanceRequest request = new CreateDBInstanceRequest();
// RDS instance name
request.setDBInstanceIdentifier("Sydney");
request.setEngine("postgres");
request.setMultiAZ(false);
request.setMasterUsername(db_username);
request.setMasterUserPassword(db_password);
request.setDBName(db_database);
request.setStorageType("gp2");
request.setAllocatedStorage(10);
CreateDbInstanceRequest instanceRequest = CreateDbInstanceRequest.builder()
.dbInstanceIdentifier("Sydney")
.engine("postgres")
.multiAZ(false)
.masterUsername(db_username)
.masterUserPassword(db_password)
.dbName(db_database)
.storageType("gp2")
.allocatedStorage(10)
.build();
DBInstance instance = amazonRDS.createDBInstance(request);
CreateDbInstanceResponse createDbInstanceResponse = rdsClient.createDBInstance(instanceRequest);
// Information about the new RDS instance
identifier = instance.getDBInstanceIdentifier();
String status = instance.getDBInstanceStatus();
Endpoint endpoint = instance.getEndpoint();
String endpoint_url = "Endpoint URL not available yet.";
identifier = createDbInstanceResponse.dbInstance().dbInstanceIdentifier();
String status = createDbInstanceResponse.dbInstance().dbInstanceStatus();
Endpoint endpoint = createDbInstanceResponse.dbInstance().endpoint();
String endpointUrl = "Endpoint URL not available yet.";
if (endpoint != null) {
endpoint_url = endpoint.toString();
endpointUrl = endpoint.toString();
}
logger.info(identifier + "\t" + status);
logger.info(endpoint_url);
logger.info(endpointUrl);
return identifier;
@ -90,44 +87,44 @@ public class AWSRDSService {
// Describe DB instances
public void listInstances() {
DescribeDBInstancesResult result = amazonRDS.describeDBInstances();
List<DBInstance> instances = result.getDBInstances();
DescribeDbInstancesResponse response = rdsClient.describeDBInstances();
List<DBInstance> instances = response.dbInstances();
for (DBInstance instance : instances) {
// Information about each RDS instance
String identifier = instance.getDBInstanceIdentifier();
String engine = instance.getEngine();
String status = instance.getDBInstanceStatus();
Endpoint endpoint = instance.getEndpoint();
String endpoint_url = "Endpoint URL not available yet.";
String identifier = instance.dbInstanceIdentifier();
String engine = instance.engine();
String status = instance.dbInstanceStatus();
Endpoint endpoint = instance.endpoint();
String endpointUrl = "Endpoint URL not available yet.";
if (endpoint != null) {
endpoint_url = endpoint.toString();
endpointUrl = endpoint.toString();
}
logger.info(identifier + "\t" + engine + "\t" + status);
logger.info("\t" + endpoint_url);
logger.info("\t" + endpointUrl);
}
}
//Delete RDS instance
public void terminateInstance(String identifier) {
DeleteDBInstanceRequest request = new DeleteDBInstanceRequest();
request.setDBInstanceIdentifier(identifier);
request.setSkipFinalSnapshot(true);
DeleteDbInstanceRequest request = DeleteDbInstanceRequest.builder()
.dbInstanceIdentifier(identifier)
.skipFinalSnapshot(true)
.build();
// Delete the RDS instance
DBInstance instance = amazonRDS.deleteDBInstance(request);
DeleteDbInstanceResponse response = rdsClient.deleteDBInstance(request);
// Information about the RDS instance being deleted
String status = instance.getDBInstanceStatus();
Endpoint endpoint = instance.getEndpoint();
String endpoint_url = "Endpoint URL not available yet.";
String status = response.dbInstance().dbInstanceStatus();
Endpoint endpoint = response.dbInstance().endpoint();
String endpointUrl = "Endpoint URL not available yet.";
if (endpoint != null) {
endpoint_url = endpoint.toString();
endpointUrl = endpoint.toString();
}
logger.info(identifier + "\t" + status);
logger.info(endpoint_url);
logger.info(endpointUrl);
}

206
aws-modules/aws-miscellaneous/src/main/java/com/baeldung/sqs/SQSApplication.java
View File

@ -5,140 +5,190 @@ import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
import com.amazonaws.services.sqs.model.CreateQueueRequest;
import com.amazonaws.services.sqs.model.DeleteMessageRequest;
import com.amazonaws.services.sqs.model.GetQueueAttributesRequest;
import com.amazonaws.services.sqs.model.GetQueueAttributesResult;
import com.amazonaws.services.sqs.model.MessageAttributeValue;
import com.amazonaws.services.sqs.model.ReceiveMessageRequest;
import com.amazonaws.services.sqs.model.SendMessageBatchRequest;
import com.amazonaws.services.sqs.model.SendMessageRequest;
import com.amazonaws.services.sqs.model.SetQueueAttributesRequest;
import com.amazonaws.services.sqs.model.SendMessageBatchRequestEntry;
import com.amazonaws.services.sqs.model.Message;
import com.amazonaws.services.sqs.AmazonSQS;
import software.amazon.awssdk.auth.credentials.ProfileCredentialsProvider;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.sqs.SqsClient;
import software.amazon.awssdk.services.sqs.model.CreateQueueRequest;
import software.amazon.awssdk.services.sqs.model.DeleteMessageRequest;
import software.amazon.awssdk.services.sqs.model.GetQueueAttributesRequest;
import software.amazon.awssdk.services.sqs.model.GetQueueAttributesResponse;
import software.amazon.awssdk.services.sqs.model.GetQueueUrlRequest;
import software.amazon.awssdk.services.sqs.model.GetQueueUrlResponse;
import software.amazon.awssdk.services.sqs.model.Message;
import software.amazon.awssdk.services.sqs.model.MessageAttributeValue;
import software.amazon.awssdk.services.sqs.model.QueueAttributeName;
import software.amazon.awssdk.services.sqs.model.ReceiveMessageRequest;
import software.amazon.awssdk.services.sqs.model.SendMessageBatchRequest;
import software.amazon.awssdk.services.sqs.model.SendMessageBatchRequestEntry;
import software.amazon.awssdk.services.sqs.model.SendMessageRequest;
import software.amazon.awssdk.services.sqs.model.SetQueueAttributesRequest;
public class SQSApplication {
private static final AWSCredentials credentials;
static {
// put your accesskey and secretkey here
credentials = new BasicAWSCredentials(
"<AWS accesskey>",
"<AWS secretkey>"
);
}
private static final String STANDARD_QUEUE_NAME = "baeldung-queue";
private static final String FIFO_QUEUE_NAME = "baeldung-queue.fifo";
private static final String DEAD_LETTER_QUEUE_NAME = "baeldung-dead-letter-queue";
public static void main(String[] args) {
// Set up the client
AmazonSQS sqs = AmazonSQSClientBuilder.standard()
.withCredentials(new AWSStaticCredentialsProvider(credentials))
.withRegion(Regions.US_EAST_1)
SqsClient sqsClient = SqsClient.builder()
.region(Region.US_EAST_1)
.credentialsProvider(ProfileCredentialsProvider.create())
.build();
// Create a standard queue
CreateQueueRequest createStandardQueueRequest = CreateQueueRequest.builder()
.queueName(STANDARD_QUEUE_NAME)
.build();
CreateQueueRequest createStandardQueueRequest = new CreateQueueRequest("baeldung-queue");
String standardQueueUrl = sqs.createQueue(createStandardQueueRequest)
.getQueueUrl();
sqsClient.createQueue(createStandardQueueRequest);
System.out.println("\nGet queue url");
GetQueueUrlResponse getQueueUrlResponse = sqsClient.getQueueUrl(GetQueueUrlRequest.builder()
.queueName(STANDARD_QUEUE_NAME)
.build());
String standardQueueUrl = getQueueUrlResponse.queueUrl();
System.out.println(standardQueueUrl);
// Create a fifo queue
Map<QueueAttributeName, String> queueAttributes = new HashMap<>();
queueAttributes.put(QueueAttributeName.FIFO_QUEUE, "true");
queueAttributes.put(QueueAttributeName.CONTENT_BASED_DEDUPLICATION, "true");
Map<String, String> queueAttributes = new HashMap<String, String>();
queueAttributes.put("FifoQueue", "true");
queueAttributes.put("ContentBasedDeduplication", "true");
CreateQueueRequest createFifoQueueRequest = CreateQueueRequest.builder()
.queueName(FIFO_QUEUE_NAME)
.attributes(queueAttributes)
.build();
CreateQueueRequest createFifoQueueRequest = new CreateQueueRequest("baeldung-queue.fifo").withAttributes(queueAttributes);
String fifoQueueUrl = sqs.createQueue(createFifoQueueRequest)
.getQueueUrl();
sqsClient.createQueue(createFifoQueueRequest);
GetQueueUrlResponse getFifoQueueUrlResponse = sqsClient.getQueueUrl(GetQueueUrlRequest.builder()
.queueName(FIFO_QUEUE_NAME)
.build());
String fifoQueueUrl = getFifoQueueUrlResponse.queueUrl();
System.out.println(fifoQueueUrl);
// Set up a dead letter queue
CreateQueueRequest createDeadLetterQueueRequest = CreateQueueRequest.builder()
.queueName(DEAD_LETTER_QUEUE_NAME)
.build();
String deadLetterQueueUrl = sqs.createQueue("baeldung-dead-letter-queue")
.getQueueUrl();
String deadLetterQueueUrl = sqsClient.createQueue(createDeadLetterQueueRequest)
.queueUrl();
GetQueueAttributesResult deadLetterQueueAttributes = sqs.getQueueAttributes(new GetQueueAttributesRequest(deadLetterQueueUrl).withAttributeNames("QueueArn"));
GetQueueAttributesRequest getQueueAttributesRequest = GetQueueAttributesRequest.builder()
.queueUrl(deadLetterQueueUrl)
.attributeNames(QueueAttributeName.QUEUE_ARN)
.build();
String deadLetterQueueARN = deadLetterQueueAttributes.getAttributes()
GetQueueAttributesResponse deadLetterQueueAttributes = sqsClient.getQueueAttributes(getQueueAttributesRequest);
String deadLetterQueueARN = deadLetterQueueAttributes.attributes()
.get("QueueArn");
SetQueueAttributesRequest queueAttributesRequest = new SetQueueAttributesRequest().withQueueUrl(standardQueueUrl)
.addAttributesEntry("RedrivePolicy", "{\"maxReceiveCount\":\"2\", " + "\"deadLetterTargetArn\":\"" + deadLetterQueueARN + "\"}");
Map<QueueAttributeName, String> attributes = new HashMap<>();
attributes.put(QueueAttributeName.REDRIVE_POLICY, "{\"maxReceiveCount\":\"5\", \"deadLetterTargetArn\":\"" + deadLetterQueueARN + "\"}");
sqs.setQueueAttributes(queueAttributesRequest);
SetQueueAttributesRequest queueAttributesRequest = SetQueueAttributesRequest.builder()
.queueUrl(standardQueueUrl)
.attributes(attributes)
.build();
sqsClient.setQueueAttributes(queueAttributesRequest);
// Send a message to a standard queue
Map<String, MessageAttributeValue> messageAttributes = new HashMap<>();
MessageAttributeValue messageAttributeValue = MessageAttributeValue.builder()
.stringValue("This is an attribute")
.dataType("String")
.build();
messageAttributes.put("AttributeOne", new MessageAttributeValue().withStringValue("This is an attribute")
.withDataType("String"));
messageAttributes.put("AttributeOne", messageAttributeValue);
SendMessageRequest sendMessageStandardQueue = new SendMessageRequest().withQueueUrl(standardQueueUrl)
.withMessageBody("A simple message.")
.withDelaySeconds(30) // Message will arrive in the queue after 30 seconds. We can use this only in standard queues
.withMessageAttributes(messageAttributes);
SendMessageRequest sendMessageStandardQueue = SendMessageRequest.builder()
.queueUrl(standardQueueUrl)
.messageBody("A simple message.")
.delaySeconds(30) // Message will arrive in the queue after 30 seconds. We can use this only in standard queues
.messageAttributes(messageAttributes)
.build();
sqs.sendMessage(sendMessageStandardQueue);
sqsClient.sendMessage(sendMessageStandardQueue);
// Send a message to a fifo queue
SendMessageRequest sendMessageFifoQueue = new SendMessageRequest().withQueueUrl(fifoQueueUrl)
.withMessageBody("FIFO Queue")
.withMessageGroupId("baeldung-group-1")
.withMessageAttributes(messageAttributes);
SendMessageRequest sendMessageFifoQueue = SendMessageRequest.builder()
.queueUrl(fifoQueueUrl)
.messageBody("FIFO Queue")
.messageGroupId("baeldung-group-1")
.messageAttributes(messageAttributes)
.build();
sqs.sendMessage(sendMessageFifoQueue);
sqsClient.sendMessage(sendMessageFifoQueue);
// Send multiple messages
List<SendMessageBatchRequestEntry> messageEntries = new ArrayList<>();
messageEntries.add(new SendMessageBatchRequestEntry().withId("id-1")
.withMessageBody("batch-1")
.withMessageGroupId("baeldung-group-1"));
messageEntries.add(new SendMessageBatchRequestEntry().withId("id-2")
.withMessageBody("batch-2")
.withMessageGroupId("baeldung-group-1"));
SendMessageBatchRequestEntry messageBatchRequestEntry1 = SendMessageBatchRequestEntry.builder()
.id("id-1")
.messageBody("batch-1")
.messageGroupId("baeldung-group-1")
.build();
SendMessageBatchRequest sendMessageBatchRequest = new SendMessageBatchRequest(fifoQueueUrl, messageEntries);
sqs.sendMessageBatch(sendMessageBatchRequest);
SendMessageBatchRequestEntry messageBatchRequestEntry2 = SendMessageBatchRequestEntry.builder()
.id("id-2")
.messageBody("batch-2")
.messageGroupId("baeldung-group-1")
.build();
messageEntries.add(messageBatchRequestEntry1);
messageEntries.add(messageBatchRequestEntry2);
SendMessageBatchRequest sendMessageBatchRequest = SendMessageBatchRequest.builder()
.queueUrl(fifoQueueUrl)
.entries(messageEntries)
.build();
sqsClient.sendMessageBatch(sendMessageBatchRequest);
// Read a message from a queue
ReceiveMessageRequest receiveMessageRequest = new ReceiveMessageRequest(fifoQueueUrl).withWaitTimeSeconds(10) // Long polling;
.withMaxNumberOfMessages(1); // Max is 10
ReceiveMessageRequest receiveMessageRequest = ReceiveMessageRequest.builder()
.waitTimeSeconds(10)
.maxNumberOfMessages(10)
.build();
List<Message> sqsMessages = sqs.receiveMessage(receiveMessageRequest)
.getMessages();
List<Message> sqsMessages = sqsClient.receiveMessage(receiveMessageRequest)
.messages();
sqsMessages.get(0)
.getAttributes();
.attributes();
sqsMessages.get(0)
.getBody();
.body();
// Delete a message from a queue
DeleteMessageRequest deleteMessageRequest = DeleteMessageRequest.builder()
.queueUrl(fifoQueueUrl)
.receiptHandle(sqsMessages.get(0)
.receiptHandle())
.build();
sqs.deleteMessage(new DeleteMessageRequest().withQueueUrl(fifoQueueUrl)
.withReceiptHandle(sqsMessages.get(0)
.getReceiptHandle()));
sqsClient.deleteMessage(deleteMessageRequest);
// Monitoring
GetQueueAttributesRequest getQueueAttributesRequest = new GetQueueAttributesRequest(standardQueueUrl).withAttributeNames("All");
GetQueueAttributesResult getQueueAttributesResult = sqs.getQueueAttributes(getQueueAttributesRequest);
System.out.println(String.format("The number of messages on the queue: %s", getQueueAttributesResult.getAttributes()
GetQueueAttributesRequest getQueueAttributesRequestForMonitoring = GetQueueAttributesRequest.builder()
.queueUrl(standardQueueUrl)
.build();
GetQueueAttributesResponse attributesResponse = sqsClient.getQueueAttributes(getQueueAttributesRequestForMonitoring);
System.out.println(String.format("The number of messages on the queue: %s", attributesResponse.attributes()
.get("ApproximateNumberOfMessages")));
System.out.println(String.format("The number of messages in flight: %s", getQueueAttributesResult.getAttributes()
System.out.println(String.format("The number of messages in flight: %s", attributesResponse.attributes()
.get("ApproximateNumberOfMessagesNotVisible")));
}

10
aws-modules/pom.xml
View File

@ -5,6 +5,14 @@
<modelVersion>4.0.0</modelVersion>
<artifactId>aws-modules</artifactId>
<name>aws-modules</name>
<dependencies>
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk-dynamodb</artifactId>
<version>1.12.523</version>
<scope>compile</scope>
</dependency>
</dependencies>
<packaging>pom</packaging>
<parent>
@ -15,6 +23,7 @@
<modules>
<module>aws-app-sync</module>
<module>aws-dynamodb</module>
<module>aws-lambda-modules</module>
<module>aws-miscellaneous</module>
<module>aws-reactive</module>
@ -24,6 +33,7 @@
<properties>
<aws-java-sdk.version>1.12.331</aws-java-sdk.version>
<aws-java-sdk-v2.version>2.20.147</aws-java-sdk-v2.version>
<maven-shade-plugin.version>3.0.0</maven-shade-plugin.version>
</properties>

1
core-java-modules/core-java-11-2/README.md
View File

@ -5,7 +5,6 @@ This module contains articles about Java 11 core features
### Relevant articles
- [Guide To Java 8 Optional](https://www.baeldung.com/java-optional)
- [Guide to Java Reflection](http://www.baeldung.com/java-reflection)
- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
- [New Features in Java 11](https://www.baeldung.com/java-11-new-features)
- [Getting the Java Version at Runtime](https://www.baeldung.com/get-java-version-runtime)
- [Invoking a SOAP Web Service in Java](https://www.baeldung.com/java-soap-web-service)

1
core-java-modules/core-java-16/README.md
View File

@ -4,5 +4,4 @@
- [Guide to mapMulti in Stream API](https://www.baeldung.com/java-mapmulti)
- [Collecting Stream Elements into a List in Java](https://www.baeldung.com/java-stream-to-list-collecting)
- [New Features in Java 16](https://www.baeldung.com/java-16-new-features)
- [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
- [Value-Based Classes in Java](https://www.baeldung.com/java-value-based-classes)

5
core-java-modules/core-java-16/src/main/java/com/baeldung/value_based_class/Point.java
View File

@ -30,6 +30,11 @@ public final class Point {
return new Point(x, y, z);
}
@Override
public String toString() {
return "Point{" + "x=" + x + ", y=" + y + ", z=" + z + '}';
}
@Override
public boolean equals(Object other) {
if (other == null || getClass() != other.getClass())

9
core-java-modules/core-java-16/src/test/java/com/baeldung/value_based_class/ValueBasedClassUnitTest.java
View File

@ -1,14 +1,17 @@
package com.baeldung.value_based_class;
import java.util.ArrayList;
import java.util.List;
import org.junit.Assert;
import org.junit.Test;
public class ValueBasedClassUnitTest {
@Test
public void givenAutoboxedAndPrimitive_whenCompared_thenReturnEquals() {
int primitive_a = 125;
Integer obj_a = 125; // this is autoboxed
Assert.assertSame(primitive_a, obj_a);
List<Integer> list = new ArrayList<>();
list.add(1); // this is autoboxed
Assert.assertEquals(list.get(0), Integer.valueOf(1));
}
@Test

89
core-java-modules/core-java-17/src/test/java/com/baeldung/recordproperties/ReadRecordPropertiesByReflectionUnitTest.java Normal file
View File

@ -0,0 +1,89 @@
package com.baeldung.recordproperties;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.lang.reflect.Field;
import java.lang.reflect.RecordComponent;
import java.util.ArrayList;
import org.junit.jupiter.api.Test;
record Player(String name, int age, Long score) {
}
public class ReadRecordPropertiesByReflectionUnitTest {
private static final Player ERIC = new Player("Eric", 28, 4242L);
@Test
void whenUsingRecordComponent_thenGetExpectedResult() {
var fields = new ArrayList<Field>();
RecordComponent[] components = Player.class.getRecordComponents();
for (var comp : components) {
try {
Field field = ERIC.getClass()
.getDeclaredField(comp.getName());
field.setAccessible(true);
fields.add(field);
} catch (NoSuchFieldException e) {
// for simplicity, error handling is skipped
}
}
assertEquals(3, fields.size());
var nameField = fields.get(0);
var ageField = fields.get(1);
var scoreField = fields.get(2);
try {
assertEquals("name", nameField.getName());
assertEquals(String.class, nameField.getType());
assertEquals("Eric", nameField.get(ERIC));
assertEquals("age", ageField.getName());
assertEquals(int.class, ageField.getType());
assertEquals(28, ageField.get(ERIC));
assertEquals("score", scoreField.getName());
assertEquals(Long.class, scoreField.getType());
assertEquals(4242L, scoreField.get(ERIC));
} catch (IllegalAccessException exception) {
// for simplicity, error handling is skipped
}
}
@Test
void whenUsingClassGetDeclaredField_thenGetExpectedResult() {
// record has no public fields
assertEquals(0, Player.class.getFields().length);
var fields = new ArrayList<Field>();
for (var field : Player.class.getDeclaredFields()) {
field.setAccessible(true);
fields.add(field);
}
assertEquals(3, fields.size());
var nameField = fields.get(0);
var ageField = fields.get(1);
var scoreField = fields.get(2);
try {
assertEquals("name", nameField.getName());
assertEquals(String.class, nameField.getType());
assertEquals("Eric", nameField.get(ERIC));
assertEquals("age", ageField.getName());
assertEquals(int.class, ageField.getType());
assertEquals(28, ageField.get(ERIC));
assertEquals("score", scoreField.getName());
assertEquals(Long.class, scoreField.getType());
assertEquals(4242L, scoreField.get(ERIC));
} catch (IllegalAccessException ex) {
// for simplicity, error handling is skipped
}
}
}

0
core-java-modules/core-java-18/README.md Normal file
View File

55
core-java-modules/core-java-18/pom.xml Normal file
View File

@ -0,0 +1,55 @@
<?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>core-java-18</artifactId>
<name>core-java-18</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-modules</artifactId>
<version>1.0.0-SNAPSHOT</version>
<relativePath>../../</relativePath>
</parent>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<release>${maven.compiler.release}</release>
<compilerArgs>--enable-preview</compilerArgs>
<source>${maven.compiler.source.version}</source>
<target>${maven.compiler.target.version}</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>${surefire.plugin.version}</version>
<configuration>
<forkCount>1</forkCount>
</configuration>
<dependencies>
<dependency>
<groupId>org.apache.maven.surefire</groupId>
<artifactId>surefire-api</artifactId>
<version>${surefire.plugin.version}</version>
</dependency>
</dependencies>
</plugin>
</plugins>
</build>
<properties>
<maven.compiler.source.version>18</maven.compiler.source.version>
<maven.compiler.target.version>18</maven.compiler.target.version>
<maven.compiler.release>18</maven.compiler.release>
<surefire.plugin.version>3.0.0-M5</surefire.plugin.version>
</properties>
</project>

27
core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/FinalizationExamples.java Normal file
View File

@ -0,0 +1,27 @@
package com.baeldung.finalization_closeable_cleaner;
import java.io.FileInputStream;
import java.io.IOException;
public class FinalizationExamples {
FileInputStream fis = null;
public void readFileOperationWithFinalization() throws IOException {
try {
fis = new FileInputStream("input.txt");
// perform operation on the file
System.out.println(fis.readAllBytes().length);
} finally {
if (fis != null)
fis.close();
}
}
public void readFileOperationWithTryWith() throws IOException {
try (FileInputStream fis = new FileInputStream("input.txt")) {
// perform operations
System.out.println(fis.readAllBytes().length);
}
}
}

48
core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyCleanerResourceClass.java Normal file
View File

@ -0,0 +1,48 @@
package com.baeldung.finalization_closeable_cleaner;
import java.lang.ref.Cleaner;
public class MyCleanerResourceClass implements AutoCloseable {
private static Resource resource;
private static final Cleaner cleaner = Cleaner.create();
private final Cleaner.Cleanable cleanable;
public MyCleanerResourceClass() {
resource = new Resource();
this.cleanable = cleaner.register(this, new CleaningState());
}
public void useResource() {
// using the resource here
resource.use();
}
@Override
public void close() {
// perform actions to close all underlying resources
this.cleanable.clean();
}
static class CleaningState implements Runnable {
CleaningState() {
// constructor
}
@Override
public void run() {
// some cleanup action
System.out.println("Cleanup done");
}
}
static class Resource {
void use() {
System.out.println("Using the resource");
}
void close() {
System.out.println("Cleanup done");
}
}
}

25
core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyCloseableResourceClass.java Normal file
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@ -0,0 +1,25 @@
package com.baeldung.finalization_closeable_cleaner;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class MyCloseableResourceClass implements AutoCloseable {
private final FileInputStream fis;
public MyCloseableResourceClass() throws FileNotFoundException {
this.fis = new FileInputStream("src/main/resources/file.txt");
}
public int getByteLength() throws IOException {
System.out.println("Some operation");
return this.fis.readAllBytes().length;
}
@Override
public void close() throws IOException {
System.out.println("Finalized object");
this.fis.close();
}
}

24
core-java-modules/core-java-18/src/main/java/com/baeldung/finalization_closeable_cleaner/MyFinalizableResourceClass.java Normal file
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@ -0,0 +1,24 @@
package com.baeldung.finalization_closeable_cleaner;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class MyFinalizableResourceClass {
private FileInputStream fis;
public MyFinalizableResourceClass() throws FileNotFoundException {
this.fis = new FileInputStream("src/main/resources/file.txt");
}
public int getByteLength() throws IOException {
System.out.println("Some operation");
return this.fis.readAllBytes().length;
}
@Override
protected void finalize() throws Throwable {
System.out.println("Finalized object");
this.fis.close();
}
}

1
core-java-modules/core-java-18/src/main/resources/file.txt Normal file
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@ -0,0 +1 @@
This is a test file.

36
core-java-modules/core-java-18/src/test/java/com/baeldung/finalization_closeable_cleaner/FinalizationCloseableCleanerUnitTest.java Normal file
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@ -0,0 +1,36 @@
package com.baeldung.finalization_closeable_cleaner;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import java.io.IOException;
import org.junit.Assert;
import org.junit.Test;
public class FinalizationCloseableCleanerUnitTest {
@Test
public void givenMyFinalizationResource_whenUsingFinalize_thenShouldClean() {
assertDoesNotThrow(() -> {
MyFinalizableResourceClass mfr = new MyFinalizableResourceClass();
mfr.getByteLength();
});
}
@Test
public void givenMyCleanerResource_whenUsingCleanerAPI_thenShouldClean() {
assertDoesNotThrow(() -> {
try (MyCleanerResourceClass myCleanerResourceClass = new MyCleanerResourceClass()) {
myCleanerResourceClass.useResource();
}
});
}
@Test
public void givenCloseableResource_whenUsingTryWith_thenShouldClose() throws IOException {
int length = 0;
try (MyCloseableResourceClass mcr = new MyCloseableResourceClass()) {
length = mcr.getByteLength();
}
Assert.assertEquals(20, length);
}
}

1
core-java-modules/core-java-arrays-convert/README.md
View File

@ -10,3 +10,4 @@ This module contains articles about arrays conversion in Java
- [Convert Java Array to Iterable](https://www.baeldung.com/java-array-convert-to-iterable)
- [Converting an int[] to HashSet in Java](https://www.baeldung.com/java-converting-int-array-to-hashset)
- [Convert an ArrayList of String to a String Array in Java](https://www.baeldung.com/java-convert-string-arraylist-array)
- [Convert Char Array to Int Array in Java](https://www.baeldung.com/java-convert-char-int-array)

67
core-java-modules/core-java-arrays-convert/src/main/java/com/baeldung/array/conversions/CharArrayToIntArrayUtils.java Normal file
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@ -0,0 +1,67 @@
package com.baeldung.array.conversions;
import java.util.Arrays;
public class CharArrayToIntArrayUtils {
static int[] usingGetNumericValueMethod(char[] chars) {
if (chars == null) {
return null;
}
int[] ints = new int[chars.length];
for (int i = 0; i < chars.length; i++) {
ints[i] = Character.getNumericValue(chars[i]);
}
return ints;
}
static int[] usingDigitMethod(char[] chars) {
if (chars == null) {
return null;
}
int[] ints = new int[chars.length];
for (int i = 0; i < chars.length; i++) {
ints[i] = Character.digit(chars[i], 10);
}
return ints;
}
static int[] usingStreamApiMethod(char[] chars) {
if (chars == null) {
return null;
}
return new String(chars).chars()
.map(c -> c - 48)
.toArray();
}
static int[] usingParseIntMethod(char[] chars) {
if (chars == null) {
return null;
}
int[] ints = new int[chars.length];
for (int i = 0; i < chars.length; i++) {
ints[i] = Integer.parseInt(String.valueOf(chars[i]));
}
return ints;
}
static int[] usingArraysSetAllMethod(char[] chars) {
if (chars == null) {
return null;
}
int[] ints = new int[chars.length];
Arrays.setAll(ints, i -> Character.getNumericValue(chars[i]));
return ints;
}
}

54
core-java-modules/core-java-arrays-convert/src/test/java/com/baeldung/array/conversions/CharArrayToIntArrayUtilsUnitTest.java Normal file
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@ -0,0 +1,54 @@
package com.baeldung.array.conversions;
import static org.junit.jupiter.api.Assertions.assertArrayEquals;
import org.junit.jupiter.api.Test;
class CharArrayToIntArrayUtilsUnitTest {
@Test
void givenCharArray_whenUsingGetNumericValueMethod_shouldGetIntArray() {
int[] expected = { 2, 3, 4, 5 };
char[] chars = { '2', '3', '4', '5' };
int[] result = CharArrayToIntArrayUtils.usingGetNumericValueMethod(chars);
assertArrayEquals(expected, result);
}
@Test
void givenCharArray_whenUsingDigitMethod_shouldGetIntArray() {
int[] expected = { 1, 2, 3, 6 };
char[] chars = { '1', '2', '3', '6' };
int[] result = CharArrayToIntArrayUtils.usingDigitMethod(chars);
assertArrayEquals(expected, result);
}
@Test
void givenCharArray_whenUsingStreamApi_shouldGetIntArray() {
int[] expected = { 9, 8, 7, 6 };
char[] chars = { '9', '8', '7', '6' };
int[] result = CharArrayToIntArrayUtils.usingStreamApiMethod(chars);
assertArrayEquals(expected, result);
}
@Test
void givenCharArray_whenUsingParseIntMethod_shouldGetIntArray() {
int[] expected = { 9, 8, 7, 6 };
char[] chars = { '9', '8', '7', '6' };
int[] result = CharArrayToIntArrayUtils.usingParseIntMethod(chars);
assertArrayEquals(expected, result);
}
@Test
void givenCharArray_whenUsingArraysSetAllMethod_shouldGetIntArray() {
int[] expected = { 4, 9, 2, 3 };
char[] chars = { '4', '9', '2', '3' };
int[] result = CharArrayToIntArrayUtils.usingArraysSetAllMethod(chars);
assertArrayEquals(expected, result);
}
}

1
core-java-modules/core-java-httpclient/src/main/java/com/baeldung/httpclient/HttpClientPost.java
View File

@ -123,6 +123,7 @@ public class HttpClientPost {
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create(serviceUrl))
.header("Content-Type", "application/x-www-form-urlencoded")
.POST(HttpRequest.BodyPublishers.ofString(getFormDataAsString(formData)))
.build();

72
core-java-modules/core-java-io-5/src/test/java/com/baeldung/rmlinebreaks/RemoveLinebreaksUnitTest.java Normal file
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@ -0,0 +1,72 @@
package com.baeldung.rmlinebreaks;
import org.junit.jupiter.api.Test;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.List;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
public class RemoveLinebreaksUnitTest {
private Path file1Path() throws Exception {
return Paths.get(this.getClass().getClassLoader().getResource("multiple-line-1.txt").toURI());
}
private Path file2Path() throws Exception {
return Paths.get(this.getClass().getClassLoader().getResource("multiple-line-2.txt").toURI());
}
@Test
void whenRemovingLineSeparatorFromFile1_thenGetTheExpectedResult() throws Exception {
String content = Files.readString(file1Path(), StandardCharsets.UTF_8);
String result = content.replace(System.getProperty("line.separator"), "");
assertEquals("A, B, C, D, E, F", result);
}
@Test
void whenRemovingLineSeparatorFromFile2_thenNotGetTheExpectedResult() throws Exception {
String content = Files.readString(file2Path(), StandardCharsets.UTF_8);
String result = content.replace(System.getProperty("line.separator"), "");
assertNotEquals("A, B, C, D, E, F", result); // <-- NOT equals assertion!
}
@Test
void whenRemovingAllLinebreaks_thenGetTheExpectedResult() throws Exception {
String content1 = Files.readString(file1Path(), StandardCharsets.UTF_8);
// file contains CRLF
String content2 = Files.readString(file2Path(), StandardCharsets.UTF_8);
String result1 = content1.replace("\r", "").replace("\n", "");
String result2 = content2.replace("\r", "").replace("\n", "");
assertEquals("A, B, C, D, E, F", result1);
assertEquals("A, B, C, D, E, F", result2);
String resultReplaceAll = content2.replaceAll("[\\n\\r]", "");
assertEquals("A, B, C, D, E, F", resultReplaceAll);
}
@Test
void whenUsingReadAllLinesAndJoin_thenGetExpectedResult() throws Exception {
List<String> lines1 = Files.readAllLines(file1Path(), StandardCharsets.UTF_8);
// file contains CRLF
List<String> lines2 = Files.readAllLines(file2Path(), StandardCharsets.UTF_8);
String result1 = String.join("", lines1);
String result2 = String.join("", lines2);
assertEquals("A, B, C, D, E, F", result1);
assertEquals("A, B, C, D, E, F", result2);
}
}

6
core-java-modules/core-java-io-5/src/test/resources/multiple-line-1.txt Normal file
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@ -0,0 +1,6 @@
A,
B,
C,
D,
E,
F

4
core-java-modules/core-java-io-5/src/test/resources/multiple-line-2.txt Normal file
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@ -0,0 +1,4 @@
A, B,
C,
D, E,
F

7
core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/Book.java Normal file
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@ -0,0 +1,7 @@
package com.baeldung.encapsulation;
public class Book {
public String author;
public int isbn;
}

8
core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookDetails.java Normal file
View File

@ -0,0 +1,8 @@
package com.baeldung.encapsulation;
public class BookDetails {
public String bookDetails(Book book) {
return "author name: " + book.author + " ISBN: " + book.isbn;
}
}

17
core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookEncapsulation.java Normal file
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@ -0,0 +1,17 @@
package com.baeldung.encapsulation;
public class BookEncapsulation {
public String author;
public int isbn;
public int id = 1;
public BookEncapsulation(String author, int isbn) {
this.author = author;
this.isbn = isbn;
}
public String getBookDetails() {
return "author id: " + id + " author name: " + author + " ISBN: " + isbn;
}
}

36
core-java-modules/core-java-lang-oop-others/src/main/java/com/baeldung/encapsulation/BookInformationHiding.java Normal file
View File

@ -0,0 +1,36 @@
package com.baeldung.encapsulation;
public class BookInformationHiding {
private String author;
private int isbn;
private int id = 1;
public BookInformationHiding(String author, int isbn) {
setAuthor(author);
setIsbn(isbn);
}
public String getAuthor() {
return author;
}
public void setAuthor(String author) {
this.author = author;
}
public int getIsbn() {
return isbn;
}
public void setIsbn(int isbn) {
if (isbn < 0) {
throw new IllegalArgumentException("ISBN can't be negative");
}
this.isbn = isbn;
}
public String getBookDetails() {
return "author id: " + id + " author name: " + author + " ISBN: " + isbn;
}
}

35
core-java-modules/core-java-lang-oop-others/src/test/java/com/baeldung/encapsulation/EncapsulationAndInformationHidingUnitTest.java Normal file
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@ -0,0 +1,35 @@
package com.baeldung.encapsulation;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
public class EncapsulationAndInformationHidingUnitTest {
@Test
public void givenUnencapsulatedClass_whenImplementationClassIsSeparate_thenReturnResult() {
Book myBook = new Book();
myBook.author = "J.K Rowlings";
myBook.isbn = 67890;
BookDetails details = new BookDetails();
String result = details.bookDetails(myBook);
assertEquals("author name: " + myBook.author + " ISBN: " + myBook.isbn, result);
}
@Test
public void givenEncapsulatedClass_whenDataIsNotHidden_thenReturnResult() {
BookEncapsulation myBook = new BookEncapsulation("J.K Rowlings", 67890);
String result = myBook.getBookDetails();
assertEquals("author id: " + 1 + " author name: " + myBook.author + " ISBN: " + myBook.isbn, result);
}
@Test
public void givenEncapsulatedClass_whenDataIsHidden_thenReturnResult() {
BookInformationHiding myBook = new BookInformationHiding("J.K Rowlings", 67890);
String result = myBook.getBookDetails();
assertEquals("author id: " + 1 + " author name: " + myBook.getAuthor() + " ISBN: " + myBook.getIsbn(), result);
}
}

25
core-java-modules/core-java-networking/src/test/java/com/baeldung/networking/url/UrlUnitTest.java
View File

@ -2,10 +2,15 @@ package com.baeldung.networking.url;
import static java.util.stream.Collectors.toList;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNotNull;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Map;
import org.apache.http.client.utils.URIBuilder;
@ -149,4 +154,24 @@ public class UrlUnitTest {
assertEquals("http://baeldung.com:9090/articles?topic=java&version=8", url.toString());
}
@Test
public void givenURI_whenConvertingToURL_thenCorrect() throws IOException, URISyntaxException {
String aURIString = "http://courses.baeldung.com";
URI uri = new URI(aURIString);
URL url = uri.toURL();
assertNotNull(url);
assertEquals(aURIString, url.toString());
}
@Test
public void givenPath_whenConvertingToURIAndThenURL_thenCorrect() throws IOException, URISyntaxException {
String finalPath = "file:/D:/baeldung/java-url";
Path path = Paths.get("/baeldung/java-url");
URI uri = path.toUri();
URL url = uri.toURL();
assertNotNull(url);
// Adapt the finalPath value to match your own path
// assertEquals(finalPath, url.toString());
}
}

18
core-java-modules/core-java-numbers-3/src/test/java/com/baeldung/integerToBinary/IntegerToBinaryUnitTest.java
View File

@ -1,6 +1,8 @@
package com.baeldung.integerToBinary;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class IntegerToBinaryUnitTest {
@ -24,4 +26,18 @@ public class IntegerToBinaryUnitTest {
String binaryString = Integer.toString(n, 2);
assertEquals("111", binaryString);
}
}
@Test
public void givenAnInteger_whenFormatAndReplaceCalled_thenZeroPaddedBinaryString() {
int n = 7;
String binaryString = String.format("%8s", Integer.toBinaryString(n)).replace(" ", "0");
assertEquals("00000111", binaryString);
}
@Test
public void givenAnInteger_whenUsingApacheStringUtils_thenZeroPaddedBinaryString() {
int n = 7;
String binaryString = StringUtils.leftPad(Integer.toBinaryString(n), 8, "0");
assertEquals("00000111", binaryString);
}
}

1
core-java-modules/core-java-numbers-6/README.md
View File

@ -5,4 +5,5 @@
- [Does Java Read Integers in Little Endian or Big Endian?](https://www.baeldung.com/java-integers-little-big-endian)
- [How to Split an Integer Number Into Digits in Java](https://www.baeldung.com/java-integer-individual-digits)
- [Java Double vs. BigDecimal](https://www.baeldung.com/java-double-vs-bigdecimal)
- [Finding the Square Root of a BigInteger in Java](https://www.baeldung.com/java-find-square-root-biginteger)
- More articles: [[<-- prev]](../core-java-numbers-5)

28
core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/BigDecimalConversionUnitTest.java Normal file
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@ -0,0 +1,28 @@
package com.baeldung.javadoublevsbigdecimal;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import java.math.BigDecimal;
import java.math.RoundingMode;
import org.junit.jupiter.api.Test;
public class BigDecimalConversionUnitTest {
@Test
void whenConvertingDoubleToBigDecimal_thenConversionIsCorrect() {
double doubleValue = 123.456;
BigDecimal bigDecimalValue = BigDecimal.valueOf(doubleValue);
BigDecimal expected = new BigDecimal("123.456").setScale(3, RoundingMode.HALF_UP);
assertEquals(expected, bigDecimalValue.setScale(3, RoundingMode.HALF_UP));
}
@Test
void givenDecimalPlacesGreaterThan15_whenConvertingBigDecimalToDouble_thenPrecisionIsLost() {
BigDecimal bigDecimalValue = new BigDecimal("789.1234567890123456");
double doubleValue = bigDecimalValue.doubleValue();
BigDecimal convertedBackToBigDecimal = BigDecimal.valueOf(doubleValue);
assertNotEquals(bigDecimalValue, convertedBackToBigDecimal);
}
}

42
core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/BigDecimalUnitTest.java Normal file
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@ -0,0 +1,42 @@
package com.baeldung.javadoublevsbigdecimal;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.math.BigDecimal;
import java.math.RoundingMode;
import org.junit.jupiter.api.Test;
public class BigDecimalUnitTest {
private BigDecimal bigDecimal1 = new BigDecimal("124567890.0987654321");
private BigDecimal bigDecimal2 = new BigDecimal("987654321.123456789");
@Test
public void givenTwoBigDecimals_whenAdd_thenCorrect() {
BigDecimal expected = new BigDecimal("1112222211.2222222211");
BigDecimal actual = bigDecimal1.add(bigDecimal2);
assertEquals(expected, actual);
}
@Test
public void givenTwoBigDecimals_whenMultiply_thenCorrect() {
BigDecimal expected = new BigDecimal("123030014929277547.5030955772112635269");
BigDecimal actual = bigDecimal1.multiply(bigDecimal2);
assertEquals(expected, actual);
}
@Test
public void givenTwoBigDecimals_whenSubtract_thenCorrect() {
BigDecimal expected = new BigDecimal("-863086431.0246913569");
BigDecimal actual = bigDecimal1.subtract(bigDecimal2);
assertEquals(expected, actual);
}
@Test
public void givenTwoBigDecimals_whenDivide_thenCorrect() {
BigDecimal expected = new BigDecimal("0.13");
BigDecimal actual = bigDecimal1.divide(bigDecimal2, 2, RoundingMode.HALF_UP);
assertEquals(expected, actual);
}
}

15
core-java-modules/core-java-numbers-6/src/test/java/com/baeldung/javadoublevsbigdecimal/JavaDoubleUnitTest.java Normal file
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@ -0,0 +1,15 @@
package com.baeldung.javadoublevsbigdecimal;
import static org.junit.jupiter.api.Assertions.*;
import org.junit.jupiter.api.Test;
public class JavaDoubleUnitTest {
@Test
public void givenDoubleLiteral_whenAssigningToDoubleVariable_thenValueIsNotExactlyEqual() {
double doubleValue = 0.1;
double epsilon = 0.0000000000000001;
assertEquals(0.1, doubleValue, epsilon);
}
}

12
core-java-modules/core-java-numbers-conversions/src/test/java/com/baeldung/floatdoubleconversions/FloatDoubleConversionsTest.java
View File

@ -9,25 +9,21 @@ public class FloatDoubleConversionsTest {
public void whenDoubleType_thenFloatTypeSuccess(){
double interestRatesYearly = 13.333333333333334;
float interest = (float) interestRatesYearly;
System.out.println(interest); //13.333333
Assert.assertTrue(Float.class.isInstance(interest));//true
Assert.assertEquals(13.333333f, interest, 0.000004f);
Double monthlyRates = 2.111111111111112;
float rates = monthlyRates.floatValue();
System.out.println(rates); //2.1111112
Assert.assertTrue(Float.class.isInstance(rates));//true
Assert.assertEquals(2.1111112f, rates, 0.00000013);
}
@Test
public void whenFloatType_thenDoubleTypeSuccess(){
float gradeAverage =2.05f;
double average = gradeAverage;
System.out.println(average); //2.049999952316284
Assert.assertTrue(Double.class.isInstance(average));//true
Assert.assertEquals(2.05, average, 0.06);
Float monthlyRates = 2.1111112f;
Double rates = monthlyRates.doubleValue();
System.out.println(rates); //2.1111112
Assert.assertTrue(Double.class.isInstance(rates));//true
Assert.assertEquals(2.11111112, rates, 0.0000002);//true
}
}

49
core-java-modules/core-java-numbers-conversions/src/test/java/com/baeldung/floattobigdecimal/FloatToBigDecimalUnitTest.java Normal file
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@ -0,0 +1,49 @@
package com.baeldung.floattobigdecimal;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotEquals;
import java.math.BigDecimal;
import org.junit.jupiter.api.Test;
class FloatToBigDecimalUnitTest {
@Test
public void whenFloatComparedWithDifferentValues_thenCouldMatch() {
assertNotEquals(1.1f, 1.09f);
assertEquals(1.1f, 1.09999999f);
}
@Test
public void whenCreatedFromFloat_thenMatchesInternallyStoredValue() {
float floatToConvert = 1.10000002384185791015625f;
BigDecimal bdFromFloat = new BigDecimal(floatToConvert);
assertEquals("1.10000002384185791015625", bdFromFloat.toString());
}
@Test
public void whenCreatedFromString_thenPreservesTheOriginal() {
BigDecimal bdFromString = new BigDecimal("1.1");
assertEquals("1.1", bdFromString.toString());
}
@Test
public void whenCreatedFromFloatConvertedToString_thenFloatInternalValueGetsTruncated() {
String floatValue = Float.toString(1.10000002384185791015625f);
BigDecimal bdFromString = new BigDecimal(floatValue);
assertEquals("1.1", floatValue);
assertEquals("1.1", bdFromString.toString());
}
@Test
public void whenCreatedByValueOf_thenFloatValueGetsTruncated() {
assertEquals("1.100000023841858", BigDecimal.valueOf(1.10000002384185791015625f).toString());
}
@Test
public void whenDoubleConvertsFloatToString_thenFloatValueGetsTruncated() {
assertEquals("1.100000023841858", Double.toString(1.10000002384185791015625f));
}
}

2
core-java-modules/core-java-reflection-3/README.md Normal file
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@ -0,0 +1,2 @@
### Relevant Articles:
- [Is Java Reflection Bad Practice?](https://www.baeldung.com/java-reflection-bad-practice)

78
core-java-modules/core-java-reflection-3/pom.xml Normal file
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@ -0,0 +1,78 @@
<?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>core-java-reflection-3</artifactId>
<name>core-java-reflection-3</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung.core-java-modules</groupId>
<artifactId>core-java-modules</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>${reflections.version}</version>
</dependency>
</dependencies>
<build>
<finalName>core-java-reflection-3</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>${source.version}</source>
<target>${target.version}</target>
<compilerArgument>-parameters</compilerArgument>
</configuration>
</plugin>
<plugin>
<groupId>org.jacoco</groupId>
<artifactId>jacoco-maven-plugin</artifactId>
<version>0.8.8</version>
<executions>
<execution>
<goals>
<goal>prepare-agent</goal>
</goals>
</execution>
<execution>
<id>report</id>
<phase>prepare-package</phase>
<goals>
<goal>report</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<properties>
<reflections.version>0.9.12</reflections.version>
<source.version>1.8</source.version>
<target.version>1.8</target.version>
<spring.version>5.3.4</spring.version>
</properties>
</project>

11
core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/encapsulation/MyClass.java Normal file
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@ -0,0 +1,11 @@
package com.baeldung.reflection.disadvantages.encapsulation;
public class MyClass {
private String veryPrivateField;
public MyClass() {
this.veryPrivateField = "Secret Information";
}
}

7
core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/BenchmarkRunner.java Normal file
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@ -0,0 +1,7 @@
package com.baeldung.reflection.disadvantages.performance;
public class BenchmarkRunner {
public static void main(String[] args) throws Exception {
org.openjdk.jmh.Main.main(args);
}
}

29
core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/InitializationBenchmark.java Normal file
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@ -0,0 +1,29 @@
package com.baeldung.reflection.disadvantages.performance;
import org.openjdk.jmh.annotations.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.util.concurrent.TimeUnit;
public class InitializationBenchmark {
@Benchmark
@Fork(value = 1, warmups = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void directInit() {
Person person = new Person("John", "Doe", 50);
}
@Benchmark
@Fork(value = 1, warmups = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void reflectiveInit() throws NoSuchMethodException, InvocationTargetException, InstantiationException, IllegalAccessException {
Constructor<Person> constructor = Person.class.getDeclaredConstructor(String.class, String.class, Integer.class);
Person person = constructor.newInstance("John", "Doe", 50);
}
}

48
core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/MethodInvocationBenchmark.java Normal file
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@ -0,0 +1,48 @@
package com.baeldung.reflection.disadvantages.performance;
import org.openjdk.jmh.annotations.*;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;
public class MethodInvocationBenchmark {
@Benchmark
@Fork(value = 1, warmups = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void directCall() {
directCall(new Person("John", "Doe", 50));
}
@Benchmark
@Fork(value = 1, warmups = 1)
@OutputTimeUnit(TimeUnit.NANOSECONDS)
@BenchmarkMode(Mode.AverageTime)
public void reflectiveCall() throws InvocationTargetException, NoSuchMethodException, IllegalAccessException {
reflectiveCall(new Person("John", "Doe", 50));
}
private void directCall(Person person) {
person.getFirstName();
person.getLastName();
person.getAge();
}
private void reflectiveCall(Person person) throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
Method getFirstNameMethod = Person.class.getMethod("getFirstName");
getFirstNameMethod.invoke(person);
Method getLastNameMethod = Person.class.getMethod("getLastName");
getLastNameMethod.invoke(person);
Method getAgeMethod = Person.class.getMethod("getAge");
getAgeMethod.invoke(person);
}
}

38
core-java-modules/core-java-reflection-3/src/main/java/com/baeldung/reflection/disadvantages/performance/Person.java Normal file
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@ -0,0 +1,38 @@
package com.baeldung.reflection.disadvantages.performance;
public class Person {
private String firstName;
private String lastName;
private Integer age;
public Person(String firstName, String lastName, Integer age) {
this.firstName = firstName;
this.lastName = lastName;
this.age = age;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}

21
core-java-modules/core-java-reflection-3/src/test/java/com/baeldung/reflection/disadvantages/encapsulation/ReflectionEncapsulationUnitTest.java Normal file
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@ -0,0 +1,21 @@
package com.baeldung.reflection.disadvantages.encapsulation;
import org.junit.jupiter.api.Test;
import java.lang.reflect.Field;
import static org.junit.jupiter.api.Assertions.assertEquals;
public class ReflectionEncapsulationUnitTest {
@Test
public void givenPrivateField_whenUsingReflection_thenIsAccessible() throws IllegalAccessException, NoSuchFieldException {
MyClass myClassInstance = new MyClass();
Field privateField = MyClass.class.getDeclaredField("veryPrivateField");
privateField.setAccessible(true);
String accessedField = privateField.get(myClassInstance).toString();
assertEquals(accessedField, "Secret Information");
}
}

14
core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/SecureConnection.java
View File

@ -7,7 +7,7 @@ import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
public class SecureConnection {
public static void main(String[] args) {
if (args.length != 2) {
System.out.println("Use: SecureConnection host port");
@ -20,20 +20,20 @@ public class SecureConnection {
SSLSocket sslsocket = (SSLSocket) sslsocketfactory.createSocket(host, port);
InputStream in = sslsocket.getInputStream();
OutputStream out = sslsocket.getOutputStream();
out.write(1);
while (in.available() > 0) {
System.out.print(in.read());
}
System.out.println("Secured connection performed successfully");
} catch (Exception exception) {
exception.printStackTrace();
}
}
/**
* Get the host from arguments
* @param args the arguments
@ -42,7 +42,7 @@ public class SecureConnection {
private static String getHost(String[] args) {
return args[0];
}
/**
* Get the port from arguments
* @param args the arguments

7
core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/example/SimpleClient.java
View File

@ -15,10 +15,8 @@ public class SimpleClient {
SocketFactory factory = SSLSocketFactory.getDefault();
try (Socket connection = factory.createSocket(host, port)) {
((SSLSocket) connection).setEnabledCipherSuites(
new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
((SSLSocket) connection).setEnabledProtocols(
new String[] { "TLSv1.2"});
((SSLSocket) connection).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
((SSLSocket) connection).setEnabledProtocols(new String[] { "TLSv1.2" });
SSLParameters sslParams = new SSLParameters();
sslParams.setEndpointIdentificationAlgorithm("HTTPS");
((SSLSocket) connection).setSSLParameters(sslParams);
@ -28,6 +26,7 @@ public class SimpleClient {
}
public static void main(String[] args) throws IOException {
System.setProperty("javax.net.debug", "ssl:handshake");
System.out.println(startClient("localhost", 8443));
}
}

8
core-java-modules/core-java-security/src/main/java/com/baeldung/ssl/example/SimpleServer.java
View File

@ -14,11 +14,10 @@ public class SimpleServer {
ServerSocketFactory factory = SSLServerSocketFactory.getDefault();
try (ServerSocket listener = factory.createServerSocket(port)) {
System.setProperty("javax.net.debug", "ssl:handshake");
((SSLServerSocket) listener).setNeedClientAuth(true);
((SSLServerSocket) listener).setEnabledCipherSuites(
new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256"});
((SSLServerSocket) listener).setEnabledProtocols(
new String[] { "TLSv1.2"});
((SSLServerSocket) listener).setEnabledCipherSuites(new String[] { "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" });
((SSLServerSocket) listener).setEnabledProtocols(new String[] { "TLSv1.2" });
while (true) {
try (Socket socket = listener.accept()) {
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
@ -29,6 +28,7 @@ public class SimpleServer {
}
public static void main(String[] args) throws IOException {
System.setProperty("javax.net.debug", "ssl:handshake");
startServer(8443);
}
}

3
core-java-modules/core-java-streams-2/README.md
View File

@ -4,12 +4,9 @@ This module contains articles about the Stream API in Java.
### Relevant Articles:
- [The Java 8 Stream API Tutorial](https://www.baeldung.com/java-8-streams)
- [Introduction to Java 8 Streams](https://www.baeldung.com/java-8-streams-introduction)
- [Java 8 Stream findFirst() vs. findAny()](https://www.baeldung.com/java-stream-findfirst-vs-findany)
- [Guide to Stream.reduce()](https://www.baeldung.com/java-stream-reduce)
- [Java IntStream Conversions](https://www.baeldung.com/java-intstream-convert)
- [Java 8 Streams peek() API](https://www.baeldung.com/java-streams-peek-api)
- [Working With Maps Using Streams](https://www.baeldung.com/java-maps-streams)
- [Collect a Java Stream to an Immutable Collection](https://www.baeldung.com/java-stream-immutable-collection)
- [How to Add a Single Element to a Stream](https://www.baeldung.com/java-stream-append-prepend)
- [Operating on and Removing an Item from Stream](https://www.baeldung.com/java-use-remove-item-stream)

2
core-java-modules/core-java-streams-2/src/test/java/com/baeldung/streams/Java8StreamApiUnitTest.java
View File

@ -1,6 +1,7 @@
package com.baeldung.streams;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -37,6 +38,7 @@ public class Java8StreamApiUnitTest {
assertEquals(list.size() - 1, size);
}
@Ignore
@Test
public void checkOrder_whenChangeQuantityOfMethodCalls_thenCorrect() {

4
core-java-modules/core-java-streams-3/README.md
View File

@ -2,8 +2,7 @@
This module contains articles about the Stream API in Java.
### Relevant Articles:
- [The Difference Between map() and flatMap()](https://www.baeldung.com/java-difference-map-and-flatmap)
### Relevant Articles:
- [How to Use if/else Logic in Java 8 Streams](https://www.baeldung.com/java-8-streams-if-else-logic)
- [The Difference Between Collection.stream().forEach() and Collection.forEach()](https://www.baeldung.com/java-collection-stream-foreach)
- [Primitive Type Streams in Java 8](https://www.baeldung.com/java-8-primitive-streams)
@ -12,5 +11,4 @@ This module contains articles about the Stream API in Java.
- [Should We Close a Java Stream?](https://www.baeldung.com/java-stream-close)
- [Returning Stream vs. Collection](https://www.baeldung.com/java-return-stream-collection)
- [Convert a Java Enumeration Into a Stream](https://www.baeldung.com/java-enumeration-to-stream)
- [When to Use a Parallel Stream in Java](https://www.baeldung.com/java-when-to-use-parallel-stream)
- More articles: [[<-- prev>]](/../core-java-streams-2)

1
core-java-modules/core-java-streams-5/README.md
View File

@ -3,3 +3,4 @@
- [Working With Empty Stream in Java](https://www.baeldung.com/java-empty-stream)
- [Aggregate Runtime Exceptions in Java Streams](https://www.baeldung.com/java-streams-aggregate-exceptions)
- [Streams vs. Loops in Java](https://www.baeldung.com/java-streams-vs-loops)
- [Partition a Stream in Java](https://www.baeldung.com/java-partition-stream)

32
core-java-modules/core-java-streams-5/src/main/java/com/baeldung/skippingelements/SkippingCollector.java Normal file
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@ -0,0 +1,32 @@
package com.baeldung.skippingelements;
import java.util.ArrayList;
import java.util.List;
import java.util.function.BinaryOperator;
import java.util.stream.Collector;
class SkippingCollector {
private static final BinaryOperator<SkippingCollector> IGNORE_COMBINE = (a, b) -> a;
private final int skip;
private final List<String> list = new ArrayList<>();
private int currentIndex = 0;
private SkippingCollector(int skip) {
this.skip = skip;
}
private void accept(String item) {
final int index = ++currentIndex % skip;
if (index == 0)
list.add(item);
}
private List<String> getResult() {
return list;
}
public static Collector<String, SkippingCollector, List<String>> collector(int skip) {
return Collector.of(() -> new SkippingCollector(skip),
SkippingCollector::accept,
IGNORE_COMBINE,
SkippingCollector::getResult);
}
}

65
core-java-modules/core-java-streams-5/src/main/java/com/baeldung/skippingelements/SkippingElements.java Normal file
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@ -0,0 +1,65 @@
package com.baeldung.skippingelements;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
public class SkippingElements {
private SkippingElements() {
}
public static List<String> skipNthElementInListWithFilter(List<String> sourceList, int n) {
return IntStream.range(0, sourceList.size())
.filter(s -> (s + 1) % n == 0)
.mapToObj(sourceList::get)
.collect(Collectors.toList());
}
public static List<String> skipNthElementInListWithIterate(List<String> sourceList, int n) {
int limit = sourceList.size() / n;
return IntStream.iterate(n - 1, i -> (i + n))
.limit(limit)
.mapToObj(sourceList::get)
.collect(Collectors.toList());
}
public static List<String> skipNthElementInListWithSublist(List<String> sourceList, int n) {
int limit = sourceList.size() / n;
return Stream.iterate(sourceList, s -> s.subList(n, s.size()))
.limit(limit)
.map(s -> s.get(n - 1))
.collect(Collectors.toList());
}
public static List<String> skipNthElementInListWithFor(List<String> sourceList, int n) {
List<String> result = new ArrayList<>();
for (int i = n - 1; i < sourceList.size(); i += n) {
result.add(sourceList.get(i));
}
return result;
}
public static List<String> skipNthElementInListWithIterator(Stream<String> sourceStream, int n) {
List<String> result = new ArrayList<>();
final Iterator<String> iterator = sourceStream.iterator();
int count = 0;
while (iterator.hasNext()) {
if (count % n == n - 1) {
result.add(iterator.next());
} else {
iterator.next();
}
++count;
}
return result;
}
public static List<String> skipNthElementInStreamWithCollector(Stream<String> sourceStream, int n) {
return sourceStream.collect(SkippingCollector.collector(n));
}
}

114
core-java-modules/core-java-streams-5/src/test/java/com/baeldung/skippingelements/SkippingElementsUnitTest.java Normal file
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@ -0,0 +1,114 @@
package com.baeldung.skippingelements;
import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.List;
import java.util.stream.Stream;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;
class SkippingElementsUnitTest {
private static Stream<Arguments> testSource() {
return Stream.of(
Arguments.of(
List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
"Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
"Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
"Thirty One", "Thirty Two", "Thirty Three"),
List.of("Three", "Six", "Nine", "Twelve", "Fifteen", "Eighteen", "Twenty One", "Twenty Four", "Twenty Seven", "Thirty", "Thirty Three"),
3),
Arguments.of(
List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
"Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
"Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
"Thirty One", "Thirty Two", "Thirty Three"),
List.of("Five", "Ten", "Fifteen", "Twenty", "Twenty Five", "Thirty"),
5),
Arguments.of(
List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
"Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
"Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
"Thirty One", "Thirty Two", "Thirty Three"),
List.of("One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten", "Eleven", "Twelve", "Thirteen",
"Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen", "Twenty", "Twenty One", "Twenty Two",
"Twenty Three", "Twenty Four", "Twenty Five", "Twenty Six", "Twenty Seven", "Twenty Eight", "Twenty Nine", "Thirty",
"Thirty One", "Thirty Two", "Thirty Three"),
1),
Arguments.of(
List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
List.of("Wednesday", "Saturday"),
3),
Arguments.of(
List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
List.of("Friday"),
5),
Arguments.of(
List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
List.of("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"),
1),
Arguments.of(
List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
"December"),
List.of("March", "June", "September", "December"),
3),
Arguments.of(
List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
"December"),
List.of("May", "October"),
5),
Arguments.of(
List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
"December"),
List.of("January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November",
"December"),
1)
);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInListWithFilterTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final List<String> actual = SkippingElements.skipNthElementInListWithFilter(input, n);
assertEquals(expected, actual);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInListWithIterateTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final List<String> actual = SkippingElements.skipNthElementInListWithIterate(input, n);
assertEquals(expected, actual);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInListWithSublistTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final List<String> actual = SkippingElements.skipNthElementInListWithSublist(input, n);
assertEquals(expected, actual);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInListWithForTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final List<String> actual = SkippingElements.skipNthElementInListWithFor(input, n);
assertEquals(expected, actual);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInStreamWithIteratorTestShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final Stream<String> inputStream = input.stream();
final List<String> actual = SkippingElements.skipNthElementInListWithIterator(inputStream, n);
assertEquals(expected, actual);
}
@ParameterizedTest
@MethodSource("testSource")
void givenListSkipNthElementInStreamWithCollectorShouldFilterNthElement(List<String> input, List<String> expected, int n) {
final Stream<String> inputStream = input.stream();
final List<String> actual = SkippingElements.skipNthElementInStreamWithCollector(inputStream, n);
assertEquals(expected, actual);
}
}

14
core-java-modules/core-java-streams-simple/README.md Normal file
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@ -0,0 +1,14 @@
## Java Streams Ebook
This module contains articles about Streams that are part of the Java Streams Ebook.
### Relevant Articles
- [Introduction to Java 8 Streams](https://www.baeldung.com/java-8-streams-introduction)
- [Guide to Java 8’s Collectors](https://www.baeldung.com/java-8-collectors)
- [Java Stream Filter with Lambda Expression](https://www.baeldung.com/java-stream-filter-lambda)
- [Working With Maps Using Streams](https://www.baeldung.com/java-maps-streams)
- [The Difference Between map() and flatMap()](https://www.baeldung.com/java-difference-map-and-flatmap)
- [When to Use a Parallel Stream in Java](https://www.baeldung.com/java-when-to-use-parallel-stream)
- [Guide to Java 8 groupingBy Collector](https://www.baeldung.com/java-groupingby-collector)
- [Guide to Stream.reduce()](https://www.baeldung.com/java-stream-reduce)

52
core-java-modules/core-java-streams-simple/pom.xml Normal file
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@ -0,0 +1,52 @@
<?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>core-java-streams-simple</artifactId>
<name>core-java-streams-simple</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung.core-java-modules</groupId>
<artifactId>core-java-modules</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<dependencies>
<dependency>
<groupId>com.pivovarit</groupId>
<artifactId>throwing-function</artifactId>
<version>${throwing-function.version}</version>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
</dependencies>
<build>
<finalName>core-java-streams-simple</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
</plugin>
</plugins>
</build>
<properties>
<throwing-function.version>1.5.1</throwing-function.version>
<maven.compiler.source.version>17</maven.compiler.source.version>
<maven.compiler.target.version>17</maven.compiler.target.version>
<maven.compiler.release>17</maven.compiler.release>
</properties>
</project>

56
core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/filter/Customer.java Normal file
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@ -0,0 +1,56 @@
package com.baeldung.streams.filter;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import javax.net.ssl.HttpsURLConnection;
public class Customer {
private String name;
private int points;
private String profilePhotoUrl;
public Customer(String name, int points) {
this(name, points, "");
}
public Customer(String name, int points, String profilePhotoUrl) {
this.name = name;
this.points = points;
this.profilePhotoUrl = profilePhotoUrl;
}
public String getName() {
return name;
}
public int getPoints() {
return points;
}
public boolean hasOver(int points) {
return this.points > points;
}
public boolean hasOverHundredPoints() {
return this.points > 100;
}
public boolean hasValidProfilePhoto() throws IOException {
URL url = new URL(this.profilePhotoUrl);
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
}
public boolean hasValidProfilePhotoWithoutCheckedException() {
try {
URL url = new URL(this.profilePhotoUrl);
HttpsURLConnection connection = (HttpsURLConnection) url.openConnection();
return connection.getResponseCode() == HttpURLConnection.HTTP_OK;
} catch (IOException e) {
throw new RuntimeException(e);
}
}
}

2
core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/groupingby/BlogPost.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/BlogPost.java
View File

@ -1,4 +1,4 @@
package com.baeldung.java_16_features.groupingby;
package com.baeldung.streams.groupingby;
import java.util.IntSummaryStatistics;

2
core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/groupingby/BlogPostType.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/BlogPostType.java
View File

@ -1,4 +1,4 @@
package com.baeldung.java_16_features.groupingby;
package com.baeldung.streams.groupingby;
public enum BlogPostType {
NEWS, REVIEW, GUIDE

2
core-java-modules/core-java-16/src/main/java/com/baeldung/java_16_features/groupingby/Tuple.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/groupingby/Tuple.java
View File

@ -1,4 +1,4 @@
package com.baeldung.java_16_features.groupingby;
package com.baeldung.streams.groupingby;
import java.util.Objects;

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/BenchmarkRunner.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/BenchmarkRunner.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/DifferentSourceSplitting.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/DifferentSourceSplitting.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/FileSearchCost.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/FileSearchCost.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MemoryLocalityCosts.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/MemoryLocalityCosts.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/MergingCosts.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/MergingCosts.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/ParallelStream.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/ParallelStream.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SequentialStream.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/SequentialStream.java
View File

0
core-java-modules/core-java-streams-3/src/main/java/com/baeldung/streams/parallel/SplittingCosts.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/parallel/SplittingCosts.java
View File

7
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/application/Application.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/application/Application.java
View File

@ -1,8 +1,7 @@
package com.baeldung.reduce.application;
package com.baeldung.streams.reduce.application;
import com.baeldung.streams.reduce.entities.User;
import com.baeldung.reduce.entities.User;
import com.baeldung.reduce.utilities.NumberUtils;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

4
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/benchmarks/JMHStreamReduceBenchMark.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/benchmarks/JMHStreamReduceBenchMark.java
View File

@ -1,6 +1,6 @@
package com.baeldung.reduce.benchmarks;
package com.baeldung.streams.reduce.benchmarks;
import com.baeldung.reduce.entities.User;
import com.baeldung.streams.reduce.entities.User;
import java.util.ArrayList;
import java.util.List;
import org.openjdk.jmh.annotations.Benchmark;

2
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/entities/Rating.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/Rating.java
View File

@ -1,4 +1,4 @@
package com.baeldung.reduce.entities;
package com.baeldung.streams.reduce.entities;
import java.util.ArrayList;
import java.util.List;

2
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/entities/Review.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/Review.java
View File

@ -1,4 +1,4 @@
package com.baeldung.reduce.entities;
package com.baeldung.streams.reduce.entities;
public class Review {

2
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/entities/User.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/entities/User.java
View File

@ -1,4 +1,4 @@
package com.baeldung.reduce.entities;
package com.baeldung.streams.reduce.entities;
public class User {

2
core-java-modules/core-java-streams-2/src/main/java/com/baeldung/reduce/utilities/NumberUtils.java → core-java-modules/core-java-streams-simple/src/main/java/com/baeldung/streams/reduce/utilities/NumberUtils.java
View File

@ -1,4 +1,4 @@
package com.baeldung.reduce.utilities;
package com.baeldung.streams.reduce.utilities;
import java.util.List;
import java.util.function.BiFunction;

13
core-java-modules/core-java-streams-simple/src/main/resources/logback.xml Normal file
View File

@ -0,0 +1,13 @@
<?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>

0
core-java-modules/core-java-streams-2/src/test/java/com/baeldung/streams/Detail.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/Detail.java
View File

0
core-java-modules/core-java-streams-2/src/test/java/com/baeldung/streams/Java8StreamsUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/Java8StreamsUnitTest.java
View File

2
core-java-modules/core-java-11-2/src/test/java/com/baeldung/collectors/Java8CollectorsUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/collectors/Java8CollectorsUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.collectors;
package com.baeldung.streams.collectors;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;

14
core-java-modules/core-java-streams/src/test/java/com/baeldung/stream/filter/StreamFilterUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/filter/StreamFilterUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.stream.filter;
package com.baeldung.streams.filter;
import org.junit.jupiter.api.Test;
import com.pivovarit.function.ThrowingPredicate;
@ -14,10 +14,10 @@ import java.util.stream.Stream;
import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
public class StreamFilterUnitTest {
class StreamFilterUnitTest {
@Test
public void givenListOfCustomers_whenFilterByPoints_thenGetTwo() {
void givenListOfCustomers_whenFilterByPoints_thenGetTwo() {
Customer john = new Customer("John P.", 15);
Customer sarah = new Customer("Sarah M.", 200);
Customer charles = new Customer("Charles B.", 150);
@ -53,7 +53,7 @@ public class StreamFilterUnitTest {
}
@Test
public void givenListOfCustomers_whenFilterByMethodReference_thenGetTwo() {
void givenListOfCustomers_whenFilterByMethodReference_thenGetTwo() {
Customer john = new Customer("John P.", 15);
Customer sarah = new Customer("Sarah M.", 200);
Customer charles = new Customer("Charles B.", 150);
@ -70,7 +70,7 @@ public class StreamFilterUnitTest {
}
@Test
public void givenListOfCustomersWithOptional_whenFilterBy100Points_thenGetTwo() {
void givenListOfCustomersWithOptional_whenFilterBy100Points_thenGetTwo() {
Optional<Customer> john = Optional.of(new Customer("John P.", 15));
Optional<Customer> sarah = Optional.of(new Customer("Sarah M.", 200));
Optional<Customer> mary = Optional.of(new Customer("Mary T.", 300));
@ -89,7 +89,7 @@ public class StreamFilterUnitTest {
}
@Test
public void givenListOfCustomers_whenFilterWithCustomHandling_thenThrowException() {
void givenListOfCustomers_whenFilterWithCustomHandling_thenThrowException() {
Customer john = new Customer("John P.", 15, "https://images.unsplash.com/photo-1543320485-d0d5a49c2b2e");
Customer sarah = new Customer("Sarah M.", 200);
Customer charles = new Customer("Charles B.", 150);
@ -103,7 +103,7 @@ public class StreamFilterUnitTest {
}
@Test
public void givenListOfCustomers_whenFilterWithThrowingFunction_thenThrowException() {
void givenListOfCustomers_whenFilterWithThrowingFunction_thenThrowException() {
Customer john = new Customer("John P.", 15, "https://images.unsplash.com/photo-1543320485-d0d5a49c2b2e");
Customer sarah = new Customer("Sarah M.", 200);
Customer charles = new Customer("Charles B.", 150);

15
core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/flatmap/map/Java8MapAndFlatMapUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/flatmap/map/Java8MapAndFlatMapUnitTest.java
View File

@ -1,6 +1,7 @@
package com.baeldung.streams.flatmap.map;
import org.junit.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
import java.util.Arrays;
import java.util.Collection;
@ -10,12 +11,12 @@ import java.util.stream.Collectors;
import java.util.stream.Stream;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
public class Java8MapAndFlatMapUnitTest {
class Java8MapAndFlatMapUnitTest {
@Test
public void givenStream_whenCalledMap_thenProduceList() {
void givenStream_whenCalledMap_thenProduceList() {
List<String> myList = Stream.of("a", "b")
.map(String::toUpperCase)
.collect(Collectors.toList());
@ -23,7 +24,7 @@ public class Java8MapAndFlatMapUnitTest {
}
@Test
public void givenStream_whenCalledFlatMap_thenProduceFlattenedList() throws Exception {
void givenStream_whenCalledFlatMap_thenProduceFlattenedList() {
List<List<String>> list = Arrays.asList(Arrays.asList("a"), Arrays.asList("b"));
System.out.println(list);
@ -33,13 +34,13 @@ public class Java8MapAndFlatMapUnitTest {
}
@Test
public void givenOptional_whenCalledMap_thenProduceOptional() {
void givenOptional_whenCalledMap_thenProduceOptional() {
Optional<String> s = Optional.of("test");
assertEquals(Optional.of("TEST"), s.map(String::toUpperCase));
}
@Test
public void givenOptional_whenCalledFlatMap_thenProduceFlattenedOptional() {
void givenOptional_whenCalledFlatMap_thenProduceFlattenedOptional() {
assertEquals(Optional.of(Optional.of("STRING")), Optional.of("string")
.map(s -> Optional.of("STRING")));

28
core-java-modules/core-java-16/src/test/java/com/baeldung/java_16_features/groupingby/JavaGroupingByCollectorUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/groupingby/JavaGroupingByCollectorUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.java_16_features.groupingby;
package com.baeldung.streams.groupingby;
import static java.util.Comparator.comparingInt;
import static java.util.stream.Collectors.averagingInt;
@ -33,13 +33,13 @@ import org.apache.commons.lang3.tuple.ImmutablePair;
import org.apache.commons.lang3.tuple.Pair;
import org.junit.jupiter.api.Test;
public class JavaGroupingByCollectorUnitTest {
class JavaGroupingByCollectorUnitTest {
private static final List<BlogPost> posts = Arrays.asList(new BlogPost("News item 1", "Author 1", BlogPostType.NEWS, 15), new BlogPost("Tech review 1", "Author 2", BlogPostType.REVIEW, 5),
new BlogPost("Programming guide", "Author 1", BlogPostType.GUIDE, 20), new BlogPost("News item 2", "Author 2", BlogPostType.NEWS, 35), new BlogPost("Tech review 2", "Author 1", BlogPostType.REVIEW, 15));
@Test
public void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
void givenAListOfPosts_whenGroupedByType_thenGetAMapBetweenTypeAndPosts() {
Map<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType));
@ -52,7 +52,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
void givenAListOfPosts_whenGroupedByTypeAndTheirTitlesAreJoinedInAString_thenGetAMapBetweenTypeAndCsvTitles() {
Map<BlogPostType, String> postsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, mapping(BlogPost::getTitle, joining(", ", "Post titles: [", "]"))));
@ -62,7 +62,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
void givenAListOfPosts_whenGroupedByTypeAndSumTheLikes_thenGetAMapBetweenTypeAndPostLikes() {
Map<BlogPostType, Integer> likesPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, summingInt(BlogPost::getLikes)));
@ -75,7 +75,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
void givenAListOfPosts_whenGroupedByTypeInAnEnumMap_thenGetAnEnumMapBetweenTypeAndPosts() {
EnumMap<BlogPostType, List<BlogPost>> postsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, () -> new EnumMap<>(BlogPostType.class), toList()));
@ -88,7 +88,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
void givenAListOfPosts_whenGroupedByTypeInSets_thenGetAMapBetweenTypesAndSetsOfPosts() {
Map<BlogPostType, Set<BlogPost>> postsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, toSet()));
@ -101,7 +101,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
void givenAListOfPosts_whenGroupedByTypeConcurrently_thenGetAMapBetweenTypeAndPosts() {
ConcurrentMap<BlogPostType, List<BlogPost>> postsPerType = posts.parallelStream()
.collect(groupingByConcurrent(BlogPost::getType));
@ -114,7 +114,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
void givenAListOfPosts_whenGroupedByTypeAndAveragingLikes_thenGetAMapBetweenTypeAndAverageNumberOfLikes() {
Map<BlogPostType, Double> averageLikesPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, averagingInt(BlogPost::getLikes)));
@ -127,7 +127,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
void givenAListOfPosts_whenGroupedByTypeAndCounted_thenGetAMapBetweenTypeAndNumberOfPosts() {
Map<BlogPostType, Long> numberOfPostsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, counting()));
@ -140,7 +140,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
void givenAListOfPosts_whenGroupedByTypeAndMaxingLikes_thenGetAMapBetweenTypeAndMaximumNumberOfLikes() {
Map<BlogPostType, Optional<BlogPost>> maxLikesPerPostType = posts.stream()
.collect(groupingBy(BlogPost::getType, maxBy(comparingInt(BlogPost::getLikes))));
@ -164,7 +164,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
void givenAListOfPosts_whenGroupedByAuthorAndThenByType_thenGetAMapBetweenAuthorAndMapsBetweenTypeAndBlogPosts() {
Map<String, Map<BlogPostType, List<BlogPost>>> map = posts.stream()
.collect(groupingBy(BlogPost::getAuthor, groupingBy(BlogPost::getType)));
@ -189,7 +189,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
void givenAListOfPosts_whenGroupedByTypeAndSummarizingLikes_thenGetAMapBetweenTypeAndSummary() {
Map<BlogPostType, IntSummaryStatistics> likeStatisticsPerType = posts.stream()
.collect(groupingBy(BlogPost::getType, summarizingInt(BlogPost::getLikes)));
@ -203,7 +203,7 @@ public class JavaGroupingByCollectorUnitTest {
}
@Test
public void givenAListOfPosts_whenGroupedByComplexMapPairKeyType_thenGetAMapBetweenPairAndList() {
void givenAListOfPosts_whenGroupedByComplexMapPairKeyType_thenGetAMapBetweenPairAndList() {
Map<Pair<BlogPostType, String>, List<BlogPost>> postsPerTypeAndAuthor = posts.stream()
.collect(groupingBy(post -> new ImmutablePair<>(post.getType(), post.getAuthor())));

2
core-java-modules/core-java-streams-2/src/test/java/com/baeldung/streams/StreamMapUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/map/StreamMapUnitTest.java
View File

@ -1,4 +1,4 @@
package com.baeldung.streams;
package com.baeldung.streams.map;
import org.junit.Before;
import org.junit.Test;

0
core-java-modules/core-java-streams-3/src/test/java/com/baeldung/streams/parallel/ForkJoinUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/parallel/ForkJoinUnitTest.java
View File

35
core-java-modules/core-java-streams-2/src/test/java/com/baeldung/reduce/StreamReduceUnitTest.java → core-java-modules/core-java-streams-simple/src/test/java/com/baeldung/streams/reduce/StreamReduceUnitTest.java
View File

@ -1,79 +1,80 @@
package com.baeldung.reduce;
package com.baeldung.streams.reduce;
import com.baeldung.reduce.entities.User;
import com.baeldung.reduce.utilities.NumberUtils;
import org.junit.Test;
import static org.assertj.core.api.Assertions.assertThat;
import com.baeldung.streams.reduce.entities.User;
import com.baeldung.streams.reduce.utilities.NumberUtils;
import org.junit.jupiter.api.Test;
import java.util.Arrays;
import java.util.List;
import static org.assertj.core.api.Assertions.assertThat;
public class StreamReduceUnitTest {
class StreamReduceUnitTest {
@Test
public void givenIntegerList_whenReduceWithSumAccumulatorLambda_thenCorrect() {
void givenIntegerList_whenReduceWithSumAccumulatorLambda_thenCorrect() {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
int result = numbers.stream().reduce(0, (subtotal, element) -> subtotal + element);
assertThat(result).isEqualTo(21);
}
@Test
public void givenIntegerList_whenReduceWithSumAccumulatorMethodReference_thenCorrect() {
void givenIntegerList_whenReduceWithSumAccumulatorMethodReference_thenCorrect() {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
int result = numbers.stream().reduce(0, Integer::sum);
assertThat(result).isEqualTo(21);
}
@Test
public void givenStringList_whenReduceWithConcatenatorAccumulatorLambda_thenCorrect() {
void givenStringList_whenReduceWithConcatenatorAccumulatorLambda_thenCorrect() {
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
String result = letters.stream().reduce("", (partialString, element) -> partialString + element);
assertThat(result).isEqualTo("abcde");
}
@Test
public void givenStringList_whenReduceWithConcatenatorAccumulatorMethodReference_thenCorrect() {
void givenStringList_whenReduceWithConcatenatorAccumulatorMethodReference_thenCorrect() {
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
String result = letters.stream().reduce("", String::concat);
assertThat(result).isEqualTo("abcde");
}
@Test
public void givenStringList_whenReduceWithUppercaseConcatenatorAccumulator_thenCorrect() {
void givenStringList_whenReduceWithUppercaseConcatenatorAccumulator_thenCorrect() {
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
String result = letters.stream().reduce("", (partialString, element) -> partialString.toUpperCase() + element.toUpperCase());
assertThat(result).isEqualTo("ABCDE");
}
@Test
public void givenUserList_whenReduceWithAgeAccumulatorAndSumCombiner_thenCorrect() {
void givenUserList_whenReduceWithAgeAccumulatorAndSumCombiner_thenCorrect() {
List<User> users = Arrays.asList(new User("John", 30), new User("Julie", 35));
int result = users.stream().reduce(0, (partialAgeResult, user) -> partialAgeResult + user.getAge(), Integer::sum);
assertThat(result).isEqualTo(65);
}
@Test
public void givenStringList_whenReduceWithParallelStream_thenCorrect() {
void givenStringList_whenReduceWithParallelStream_thenCorrect() {
List<String> letters = Arrays.asList("a", "b", "c", "d", "e");
String result = letters.parallelStream().reduce("", String::concat);
assertThat(result).isEqualTo("abcde");
}
@Test
public void givenNumberUtilsClass_whenCalledDivideListElements_thenCorrect() {
void givenNumberUtilsClass_whenCalledDivideListElements_thenCorrect() {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
assertThat(NumberUtils.divideListElements(numbers, 1)).isEqualTo(21);
}
@Test
public void givenNumberUtilsClass_whenCalledDivideListElementsWithExtractedTryCatchBlock_thenCorrect() {
void givenNumberUtilsClass_whenCalledDivideListElementsWithExtractedTryCatchBlock_thenCorrect() {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
assertThat(NumberUtils.divideListElementsWithExtractedTryCatchBlock(numbers, 1)).isEqualTo(21);
}
@Test
public void givenStream_whneCalleddivideListElementsWithApplyFunctionMethod_thenCorrect() {
void givenStream_whneCalleddivideListElementsWithApplyFunctionMethod_thenCorrect() {
List<Integer> numbers = Arrays.asList(1, 2, 3, 4, 5, 6);
assertThat(NumberUtils.divideListElementsWithApplyFunctionMethod(numbers, 1)).isEqualTo(21);
}

1
core-java-modules/core-java-streams/README.md
View File

@ -9,7 +9,6 @@ This module contains articles about the Stream API in Java.
- [Iterable to Stream in Java](https://www.baeldung.com/java-iterable-to-stream)
- [How to Iterate Over a Stream With Indices](https://www.baeldung.com/java-stream-indices)
- [Stream Ordering in Java](https://www.baeldung.com/java-stream-ordering)
- [Java Stream Filter with Lambda Expression](https://www.baeldung.com/java-stream-filter-lambda)
- [Counting Matches on a Stream Filter](https://www.baeldung.com/java-stream-filter-count)
- [Summing Numbers with Java Streams](https://www.baeldung.com/java-stream-sum)
- [How to Find All Getters Returning Null](https://www.baeldung.com/java-getters-returning-null)

7
core-java-modules/core-java-streams/pom.xml
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@ -29,11 +29,6 @@
<artifactId>streamex</artifactId>
<version>${streamex.version}</version>
</dependency>
<dependency>
<groupId>com.pivovarit</groupId>
<artifactId>throwing-function</artifactId>
<version>${throwing-function.version}</version>
</dependency>
</dependencies>
<build>
@ -62,8 +57,6 @@
<vavr.version>0.10.4</vavr.version>
<protonpack.version>1.16</protonpack.version>
<streamex.version>0.8.1</streamex.version>
<throwing-function.version>1.5.1</throwing-function.version>
<maven.compiler.source>17</maven.compiler.source>
<maven.compiler.target>17</maven.compiler.target>
</properties>

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