This example will show you how to work with expected exception using Junit 5 Assertions.assetThrows(). Junit 4 (at least 4.7 version) provides expected attribute with @Test annotation, where you can mention what exception you are expecting from your test method but Junit 5 does not provide such thing. Junit 5 provides assertThrows() that can be…

In this example I am going to show you how to mock an autowired field in Spring boot framework with Junit 5. When you use @Value annotation in Spring beans to read the value from properties file and later when you want to perform Junit test then you also need to pass value for this…

I am going to show you how to work with parallel stream in Java 8 or higher version of Java. In parallel computing a task is divided into sub-tasks and these sub-tasks are computed parallelly in each separate threads and finally the result of the solution for each sub-tasks is combined. One of the features…

Table of Contents Introduction Why do you need to pretty print JSON data? Prerequisites pretty Print JSON Using Jackson Library Using Google GSON Library Using JSON Library Source Code Introduction Here I am going to show you how to pretty print JSON in Java. I am going to use here JSON, Jackson and Google Gson…

I am going to show yo how to download PDF file from MySQL database using Spring Boot and iText library in Java programming language. Many applications require dynamic generation of PDF documents for reporting purpose, such as, generating statements for customers, readers buying online specific chapters of a book, etc. In my another tutorial I…

In this example I going to show you how to convert PDF file to CSV file. I will read the PDF file using iText library and write data to the CSV file using Java programming language. In my previous example I had shown how to convert CSV file to PDF file using iText library. As…

Here I am going to tell you how to convert CSV to PDF file using iText library in Java programming language. I am going to use Java 7 or later version’s new feature Path API to read the CSV file and Java 8’s Stream API to split the comma separated line or record. I am…

Introduction Here I am going to write Junit test case for testing multiple files upload in Spring REST Controller. I have already created how to upload multiple files using Spring REST API and I also had shown how to test it through REST client tool – Postman. In this tutorial I am going to use…

In this tutorial I am going to show you how to work with Mockito‘s doNothing() in Java Junit 5 API. Mockito‘s doNothing() or Mockito itself is widely used testing framework. If you are working with Junit 4 then you can read the similar example Mockito’s doNothing() using Junit 4. Mockito‘s doNothing() is used when you…

In this example I am going to discuss on how to post image tweets to Twitter using Twitter4j Java API. Twitter4j is an unofficial Java library and using this you can easily integrate Java application with Twitter service. Using image tweets I want to mean that I want to post text as well as image…

Here we will discuss how to select single or multiple records using JDBC API. To select single record from database we use executeQuery() and to select multiple records we use executeQueryForList(). You may need to use executeQuery() to fetch single record from the database for various reasons, such as: You want to see details for…

Introduction Here I am going to tell you how to insert and update a list of objects in batch using JDBC PreparedStatement in Java programming language. Generally when you have a list of objects or lots of data then probably it is not a good idea to insert or update individual record or object into…