How-to articles, tricks, and solutions about JAVA

Mockito is a popular mocking framework for Java. It allows you to create mock objects and set up test behavior for them.

To verify that a method was called on an object created within a method using Mockito, you can use the Mockito.verify() method and pass it the object that you want to verify, as well as the method that you want to verify was called.

To mock and assert a thrown exception in Mockito, you can use the doThrow() method and the verify() method.

If you are using MySQL JDBC Driver version 5.1.33 and you are experiencing issues with time zones, there are a few things you can try:

This error typically occurs when you are trying to use the log4j library to log messages in your Java application, but the library is not properly configured.

This error message means that the Java compiler (javac) is not available in the current environment. This can happen if you are running a Java program from a Java Runtime Environment (JRE) rather than a Java Development Kit (JDK).

If you are seeing the error "No Persistence provider for EntityManager named [persistence-unit-name]" in your Java application, it means that the persistence provider (e.g.

In Java, a non-static (also known as an instance) variable or method can only be accessed from an instance of the class. A static (also known as a class) variable or method, on the other hand, can be accessed directly from the class, without the need for

To get the number of lines in a file in Java, you can use the BufferedReader class and read the file line by line until the end of the file is reached.

If you want to use the @JsonIgnore annotation to ignore a field during serialization but not during deserialization, you can use the @JsonIgnoreProperties annotation and set its writeOnly property to true.

The error org.xml.sax.SAXParseException: Content is not allowed in prolog usually indicates that there is some content before the XML prolog in the file you are trying to parse.

To scroll up or down in a web page using Selenium WebDriver in Java, you can use the JavascriptExecutor interface and the scrollBy method.

To parse a JSON object in Java, you can use the org.json library.

To parse a JSON string in Java, you can use the JSONObject class from the org.json package.

A pop-up message box is a small window that appears on a computer screen to display a message or prompt the user to take a specific action.

To make a POST request with the RestTemplate in JSON, you can use the postForObject() method and pass it the URL of the request, the request body, the response type, and the HttpEntity object that represents the request headers and body.

To print the contents of a HashMap in Java, you can use the entrySet() method to get a set of key-value pairs and then iterate over the set to print the keys and values.

To shuffle an array randomly in Java, you can use the Collections.shuffle method.

To read and write a string from and to a file in Android, you can use the FileInputStream and FileOutputStream classes along with the InputStreamReader and OutputStreamWriter classes.

This code opens the file "filename.txt" and reads it line by line. Each line is printed to the console until the end of the file is reached.

To read a properties file in Java, you can use the Properties class from the java.util package.

Received fatal alert: handshake_failure is an error message that can occur during an SSL/TLS handshake.

To handle clicks on items in a RecyclerView, you can set an OnClickListener on the View that represents each item in the RecyclerView.

To redirect to an external URL from a controller action in Spring MVC, you can use the RedirectView class and return it from the controller action.

To get the value of a generic field using reflection in Java, you can use the get() method of the Field class, which returns the value of the field as an Object.