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This tutorial will demonstrate how One-to-One Mapping in Hibernate/Spring Boot Data JPA works. As a database, I will use a MySQL database server. We will create two JPA entities: the Book and the Story. The Book and the Story entities have one to one relationship, which means that the Book entity has a Story entity,…

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We often need to compare two ArrayList in Java. In this post, you will learn how to do that in two ways: Using the ArrayList.equals() method Using the CollectionUtils.isEqualCollection() method Compare two ArrayList in Java using the ArrayList.equals() method The ArrayList.equals() method compares two ArrayList. It compares the sizes of the lists, elements equality, and the…

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Jackson is a popular Java library that provides powerful tools for converting JSON objects to Java objects and vice versa. In this tutorial, we will explore the different ways of mapping JSON objects to Java objects using Jackson. We’ll also look at how to handle dynamic JSON objects and cover some useful Jackson annotations that…

Read More Master Mapping JSON Objects to Java Objects with Jackson

In the previous lesson, we covered converting Java Object to JSON. Here, you will learn how to convert JSON to Java Object using the ObjectMapper class from the Jackson library. How to convert JSON to Java Object? We will use the readValue() method from the ObjectMapper class. There are a few overloaded readValue() methods. We will use the one that accepts…

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Sometimes we need to consume HTTPS endpoints that do not have valid certificates.  We can do that by configuring the Java HttpClient to accept all SSL certificates, even from an untrusted Certificate Authority. Here you will see how to communicate with HTTPS endpoint that may not have a valid SSL certificate. In the following example,…

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import org.apache.http.HttpResponse; import org.apache.http.HttpHeaders; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.client.methods.RequestBuilder; import org.apache.http.impl.client.BasicResponseHandler; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import java.io.IOException; public class Test { public static void main(String[] args) throws IOException { try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpUriRequest request = RequestBuilder.get() .setUri(“https://jsonplaceholder.typicode.com/todos/1”) // adding headers .setHeader(HttpHeaders.CONTENT_TYPE, “application/json”) .setHeader(“Authorization”, “Bearer 123token”) .build(); System.out.println(“Executing GET request…”); HttpResponse response = httpclient.execute(request);…

Read More Add a Custom HTTP Header with the HttpClient

<dependency> <groupid>org.apache.httpcomponents</groupid> <artifactid>httpclient</artifactid> <version>4.5.13</version> </dependency> import org.apache.http.HttpHeaders; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpDelete; import org.apache.http.impl.client.BasicResponseHandler; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import java.io.IOException; public class Test { public static void main(String[] args) throws IOException { try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpDelete httpget = new HttpDelete(“https://jsonplaceholder.typicode.com/todos/1”); System.out.println(“Executing DELETE request…”); HttpResponse response = httpclient.execute(httpget); System.out.println(“Status code: ” + response.getStatusLine().getStatusCode()); String…

Read More How to Execute an HTTP DELETE Request in Java (Solved!)

<dependency> <groupid>org.apache.httpcomponents</groupid> <artifactid>httpclient</artifactid> <version>4.5.13</version> </dependency> import org.apache.http.HttpHeaders; import org.apache.http.HttpResponse; import org.apache.http.client.methods.HttpPut; import org.apache.http.impl.client.BasicResponseHandler; import org.apache.http.impl.client.CloseableHttpClient; import org.apache.http.impl.client.HttpClients; import java.io.IOException; public class Test { public static void main(String[] args) throws IOException { try (CloseableHttpClient httpclient = HttpClients.createDefault()) { HttpPut httpPut = new HttpPut(“https://jsonplaceholder.typicode.com/posts/1”); // specify the PUT body to send to the server as part of…

Read More How to Execute an HTTP PUT Request in Java