Merge branch 'master' of https://github.com/jsgrah-spring/tutorials

algorithms-modules/algorithms-sorting-2/README.md

@@ -4,4 +4,5 @@
 - [Sorting Strings by Contained Numbers in Java](https://www.baeldung.com/java-sort-strings-contained-numbers)
 - [Guide to In-Place Sorting Algorithm Works with a Java Implementation](https://www.baeldung.com/java-in-place-sorting)
 - [Partitioning and Sorting Arrays with Many Repeated Entries with Java Examples](https://www.baeldung.com/java-sorting-arrays-with-repeated-entries)
+- [Gravity/Bead Sort in Java](https://www.baeldung.com/java-gravity-bead-sort)
 - More articles: [[<-- prev]](/algorithms-sorting)

core-java-modules/core-java-collections-set-2/README.md

@@ -1,3 +1,4 @@
 ## Relevant articles
 
 - [Using Streams to Collect Into a TreeSet](https://www.baeldung.com/java-stream-collect-into-treeset)
+- [A Guide to LinkedHashSet in Java](https://www.baeldung.com/java-linkedhashset)

core-java-modules/core-java-lang-math-3/src/main/java/com/baeldung/math/standarddeviation/StandardDeviation.java

@@ -0,0 +1,35 @@
+package com.baeldung.math.standarddeviation;
+
+import java.util.Arrays;
+
+public class StandardDeviation {
+
+    public static double calculateStandardDeviation(double[] array) {
+
+        // get the sum of array
+        double sum = 0.0;
+        for (double i : array) {
+            sum += i;
+        }
+
+        // get the mean of array
+        int length = array.length;
+        double mean = sum / length;
+
+        // calculate the standard deviation
+        double standardDeviation = 0.0;
+        for (double num : array) {
+            standardDeviation += Math.pow(num - mean, 2);
+        }
+
+        return Math.sqrt(standardDeviation / length);
+    }
+
+    public static void main(String[] args) {
+        double[] array = {25, 5, 45, 68, 61, 46, 24, 95};
+        System.out.println("List of elements: " + Arrays.toString(array));
+
+        double standardDeviation = calculateStandardDeviation(array);
+        System.out.format("Standard Deviation = %.6f", standardDeviation);
+    }
+}

core-java-modules/core-java-networking-4/README.md

@@ -0,0 +1,2 @@
+## Relevant Articles:
+- [Difference Between URI.create() and new URI()](https://www.baeldung.com/java-uri-create-and-new-uri)

libraries-data/pom.xml

@@ -174,7 +174,7 @@
         <gson.version>2.8.2</gson.version>
         <cache.version>1.1.1</cache.version>
         <flink.version>1.5.0</flink.version>
-        <hazelcast.version>3.8.4</hazelcast.version>
+        <hazelcast.version>5.2.0</hazelcast.version>
         <org.apache.crunch.crunch-core.version>0.15.0</org.apache.crunch.crunch-core.version>
         <org.apache.hadoop.hadoop-client>2.2.0</org.apache.hadoop.hadoop-client>
         <jmapper.version>1.6.0.1</jmapper.version>

libraries-data/src/test/java/com/baeldung/jcache/CacheLoaderIntegrationTest.java

@@ -16,21 +16,22 @@ import org.junit.Test;
 public class CacheLoaderIntegrationTest {
 
     private static final String CACHE_NAME = "SimpleCache";
+    private static final String HAZELCAST_MEMBER_CACHING_PROVIDER = "com.hazelcast.cache.HazelcastMemberCachingProvider";
 
     private Cache<Integer, String> cache;
 
     @Before
     public void setup() {
         // Adding fully qualified class name because of multiple Cache Provider (Ignite and Hazelcast)
-        CachingProvider cachingProvider = Caching.getCachingProvider("com.hazelcast.cache.HazelcastCachingProvider");
+        CachingProvider cachingProvider = Caching.getCachingProvider(HAZELCAST_MEMBER_CACHING_PROVIDER);
         CacheManager cacheManager = cachingProvider.getCacheManager();
         MutableConfiguration<Integer, String> config = new MutableConfiguration<Integer, String>().setReadThrough(true).setCacheLoaderFactory(new FactoryBuilder.SingletonFactory<>(new SimpleCacheLoader()));
-        this.cache = cacheManager.createCache("SimpleCache", config);
+        this.cache = cacheManager.createCache( CACHE_NAME, config );
     }
 
     @After
     public void tearDown() {
-        Caching.getCachingProvider("com.hazelcast.cache.HazelcastCachingProvider").getCacheManager().destroyCache(CACHE_NAME);
+        Caching.getCachingProvider(HAZELCAST_MEMBER_CACHING_PROVIDER).getCacheManager().destroyCache(CACHE_NAME);
     }
 
     @Test

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/DateNotifier.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 import java.util.Date;
 

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/Main.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 import java.util.Date;
 

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/Notifier.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 public interface Notifier<T> {
 

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/NotifierFactory.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 import java.util.Date;
 

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/Record.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 import java.util.Date;
 

patterns-modules/design-patterns-creational/src/main/java/com/baeldung/factorygeneric/StringNotifier.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 public class StringNotifier implements Notifier<String> {
 

patterns-modules/design-patterns-creational/src/test/java/com/baeldung/factorygeneric/FactoryGenericUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung.factoryGeneric;
+package com.baeldung.factorygeneric;
 
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.*;

rxjava-modules/rxjava-core/src/test/java/com/baeldung/rxjava/RxJavaRetryWithDelayUnitTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.rxjava;
+import io.reactivex.Observable;
+import org.junit.Test;
+
+import java.util.concurrent.TimeUnit;
+
+public class RxJavaRetryWithDelayUnitTest {
+
+    @Test
+    public void givenObservable_whenSuccess_thenOnNext(){
+        Observable.just(remoteCallSuccess())
+                .subscribe(success -> {
+                    System.out.println("Success");
+                    System.out.println(success);
+                }, err -> {
+                    System.out.println("Error");
+                    System.out.println(err);
+                });
+    }
+
+
+    @Test
+    public void givenObservable_whenError_thenOnError(){
+        Observable.just(remoteCallError())
+                .subscribe(success -> {
+                    System.out.println("Success");
+                    System.out.println(success);
+                }, err -> {
+                    System.out.println("Error");
+                    System.out.println(err);
+                });
+    }
+
+    @Test
+    public void givenError_whenRetry_thenCanDelay(){
+        Observable.just(remoteCallError())
+                .retryWhen(attempts -> {
+                    return attempts.flatMap(err -> {
+                        if (customChecker(err)) {
+                            return Observable.timer(5000, TimeUnit.MILLISECONDS);
+                        } else {
+                            return Observable.error(err);
+                        }
+                    });
+                });
+    }
+
+
+    private String remoteCallSuccess(){
+        return "Success";
+    }
+
+    private String remoteCallError(){
+        // consider a network call that failed over here.
+        return "Error";
+    }
+
+    private boolean customChecker(Throwable t){
+        // this will include custom logic that decides whether resubscription should occur or not
+        return true;
+    }
+}

spring-5-webflux-2/README.md

@@ -5,3 +5,4 @@ This module contains articles about Spring 5 WebFlux
 ## Relevant articles:
 - [Spring Webflux and @Cacheable Annotation](https://www.baeldung.com/spring-webflux-cacheable)
 - [Comparison Between Mono’s doOnNext() and doOnSuccess()](https://www.baeldung.com/mono-doonnext-doonsuccess)
+- [How to Access the First Element of a Flux](https://www.baeldung.com/java-flux-first-element)

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/ExceptionHandlingSpringApplication.java

@@ -0,0 +1,13 @@
+package com.baeldung.camel.exception;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ExceptionHandlingSpringApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ExceptionHandlingSpringApplication.class, args);
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/ExceptionHandlingWithDoTryRoute.java

@@ -0,0 +1,26 @@
+package com.baeldung.camel.exception;
+
+import java.io.IOException;
+
+import org.apache.camel.builder.RouteBuilder;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ExceptionHandlingWithDoTryRoute extends RouteBuilder {
+
+    @Override
+    public void configure() throws Exception {
+        
+        from("direct:start-handling-exception")
+            .routeId("exception-handling-route")
+            .doTry()
+                .process(new IllegalArgumentExceptionThrowingProcessor())
+                .to("mock:received")
+            .doCatch(IOException.class, IllegalArgumentException.class)
+                .to("mock:caught")
+            .doFinally()
+                .to("mock:finally")
+            .end();    
+                    
+    }
+}

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/ExceptionHandlingWithExceptionClauseRoute.java

@@ -0,0 +1,24 @@
+package com.baeldung.camel.exception;
+
+import org.apache.camel.builder.RouteBuilder;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ExceptionHandlingWithExceptionClauseRoute extends RouteBuilder {
+    
+    @Autowired
+    private ExceptionLoggingProcessor exceptionLogger;
+    
+    @Override
+    public void configure() throws Exception {
+        onException(IllegalArgumentException.class).process(exceptionLogger)
+            .handled(true)
+            .to("mock:handled");
+        
+        from("direct:start-exception-clause")
+            .routeId("exception-clause-route")
+            .process(new IllegalArgumentExceptionThrowingProcessor())
+            .to("mock:received");
+    }
+}

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/ExceptionLoggingProcessor.java

@@ -0,0 +1,30 @@
+package com.baeldung.camel.exception;
+
+import java.util.Map;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.Processor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ExceptionLoggingProcessor implements Processor {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionLoggingProcessor.class);
+
+    @Override
+    public void process(Exchange exchange) throws Exception {
+        Map<String, Object> headersMap = exchange.getIn().getHeaders();
+
+        if (!headersMap.isEmpty()) {
+            headersMap.entrySet()
+                .stream()
+                .forEach(e -> LOGGER.info("Header key [{}] -||- Header value [{}]", e.getKey(), e.getValue()));
+        } else {
+            LOGGER.info("Empty header");
+        }
+
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/ExceptionThrowingRoute.java

@@ -0,0 +1,30 @@
+package com.baeldung.camel.exception;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.Processor;
+import org.apache.camel.builder.RouteBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class ExceptionThrowingRoute extends RouteBuilder {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionThrowingRoute.class);
+
+    @Override
+    public void configure() throws Exception {
+        
+        from("direct:start-exception")
+            .routeId("exception-throwing-route")
+            .process(new Processor() {
+                
+                @Override
+                public void process(Exchange exchange) throws Exception {
+                    LOGGER.error("Exception Thrown");
+                    throw new IllegalArgumentException("An exception happened on purpose");
+                    
+                }
+            }).to("mock:received");
+    }
+}

spring-boot-modules/spring-boot-camel/src/main/java/com/baeldung/camel/exception/IllegalArgumentExceptionThrowingProcessor.java

@@ -0,0 +1,20 @@
+package com.baeldung.camel.exception;
+
+import org.apache.camel.Exchange;
+import org.apache.camel.Processor;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+@Component
+public class IllegalArgumentExceptionThrowingProcessor implements Processor {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ExceptionLoggingProcessor.class);
+
+    @Override
+    public void process(Exchange exchange) throws Exception {
+        LOGGER.error("Exception Thrown");
+        throw new IllegalArgumentException("An exception happened on purpose");
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/test/java/com/baeldung/camel/exception/ExceptionHandlingWithDoTryRouteUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.camel.exception;
+
+import org.apache.camel.EndpointInject;
+import org.apache.camel.ProducerTemplate;
+import org.apache.camel.component.mock.MockEndpoint;
+import org.apache.camel.test.spring.junit5.CamelSpringBootTest;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+@CamelSpringBootTest
+class ExceptionHandlingWithDoTryRouteUnitTest {
+
+    @Autowired
+    private ProducerTemplate template;
+
+    @EndpointInject("mock:caught")
+    private MockEndpoint mock;
+
+    @Test
+    void whenSendHeaders_thenExceptionRaisedAndHandledSuccessfully() throws Exception {
+        mock.expectedMessageCount(1);
+
+        template.sendBodyAndHeader("direct:start-handling-exception", null, "fruit", "Banana");
+
+        mock.assertIsSatisfied();
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/test/java/com/baeldung/camel/exception/ExceptionHandlingWithExceptionClauseRouteUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.camel.exception;
+
+import org.apache.camel.EndpointInject;
+import org.apache.camel.ProducerTemplate;
+import org.apache.camel.component.mock.MockEndpoint;
+import org.apache.camel.test.spring.junit5.CamelSpringBootTest;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+@CamelSpringBootTest
+class ExceptionHandlingWithExceptionClauseRouteUnitTest {
+
+    @Autowired
+    private ProducerTemplate template;
+    
+    @EndpointInject("mock:handled")
+    private MockEndpoint mock;
+    
+    @Test
+    void whenSendHeaders_thenExceptionRaisedAndHandledSuccessfully() throws Exception {
+        mock.expectedMessageCount(1);
+        
+        template.sendBodyAndHeader("direct:start-exception-clause", null, "fruit", "Banana");
+        
+        mock.assertIsSatisfied();
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/test/java/com/baeldung/camel/exception/ExceptionThrowingRouteUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.camel.exception;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.apache.camel.CamelContext;
+import org.apache.camel.Exchange;
+import org.apache.camel.ExchangePattern;
+import org.apache.camel.ProducerTemplate;
+import org.apache.camel.test.spring.junit5.CamelSpringBootTest;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+@CamelSpringBootTest
+class ExceptionThrowingRouteUnitTest {
+
+    @Autowired
+    private ProducerTemplate template;
+
+    @Test
+    void whenSendBody_thenExceptionRaisedSuccessfully() {
+        CamelContext context = template.getCamelContext();
+        Exchange exchange = context.getEndpoint("direct:start-exception")
+            .createExchange(ExchangePattern.InOut);
+
+        exchange.getIn().setBody("Hello Baeldung");
+        Exchange out = template.send("direct:start-exception", exchange);
+
+        assertTrue(out.isFailed(), "Should be failed");
+        assertTrue(out.getException() instanceof IllegalArgumentException, "Should be IllegalArgumentException");
+        assertEquals("An exception happened on purpose", out.getException().getMessage());
+    }
+
+}

spring-boot-modules/spring-boot-camel/src/test/java/com/baeldung/camel/exception/IllegalArgumentExceptionThrowingProcessorUnitTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.camel.exception;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import org.junit.jupiter.api.Test;
+
+class IllegalArgumentExceptionThrowingProcessorUnitTest {
+
+    @Test
+    void whenProcessed_thenIllegalArgumentExceptionRaisedSuccessfully() {
+        assertThrows(IllegalArgumentException.class, () -> {
+            new IllegalArgumentExceptionThrowingProcessor().process(null);
+        });
+    }
+
+}

spring-boot-modules/spring-boot-groovy/README.md

@@ -6,4 +6,5 @@ This module contains articles about Spring with Groovy
 ### Relevant Articles:
 
 - [Building a Simple Web Application with Spring Boot and Groovy](https://www.baeldung.com/spring-boot-groovy-web-app)
-- [Groovy Bean Definitions](https://www.baeldung.com/spring-groovy-beans)
+- [Groovy Bean Definitions](https://www.baeldung.com/spring-groovy-beans)
+- [Using Groovy in Spring](https://www.baeldung.com/groovy/spring-using-groovy)

spring-boot-modules/spring-boot-properties-3/README.md

@@ -8,4 +8,5 @@
 - [How to Define a Map in YAML for a POJO?](https://www.baeldung.com/yaml-map-pojo)
 - [Using application.yml vs application.properties in Spring Boot](https://www.baeldung.com/spring-boot-yaml-vs-properties)
 - [Load Spring Boot Properties From a JSON File](https://www.baeldung.com/spring-boot-json-properties)
-- [IntelliJ – Cannot Resolve Spring Boot Configuration Properties Error](https://www.baeldung.com/intellij-resolve-spring-boot-configuration-properties)
+- [IntelliJ – Cannot Resolve Spring Boot Configuration Properties Error](https://www.baeldung.com/intellij-resolve-spring-boot-configuration-properties)
+- [Log Properties in a Spring Boot Application](https://www.baeldung.com/spring-boot-log-properties)

spring-reactive-modules/spring-5-reactive-client-2/README.md

@@ -6,4 +6,5 @@ This module contains articles about reactive Spring 5 WebClient
 The "REST With Spring" Classes: http://bit.ly/restwithspring
 
 ### Relevant Articles
+- [Limiting the Requests per Second With WebClient](https://www.baeldung.com/spring-webclient-limit-requests-per-second)
 - More articles: [[<-- prev]](../spring-5-reactive-client)

testing-modules/junit-5/README.md

@@ -8,3 +8,4 @@
 - [Determine the Execution Time of JUnit Tests](https://www.baeldung.com/junit-test-execution-time)
 - [@BeforeAll and @AfterAll in Non-Static Methods](https://www.baeldung.com/java-beforeall-afterall-non-static)
 - [The java.lang.NoClassDefFoundError in JUnit](https://www.baeldung.com/junit-noclassdeffounderror)
+- [assertAll() vs Multiple Assertions in JUnit5](https://github.com/eugenp/tutorials/tree/master/testing-modules/junit-5)