Java main method is the entry point of any Java program. It’s the method that the Java Virtual Machine (JVM) calls to execute the program. In this tutorial, we’ll explore what the main method is, how it’s executed, and what the valid Java main method signatures are. We’ll also discuss some best practices for writing…
Read More Java Main Method: A Comprehensive GuideJava.io package contains a PrintStream class with two formatting methods: format() and printf(). This tutorial will teach formatting output with printf() in Java. Here, we will first deconstruct the printf() syntax. After that, we will practice a few of the examples through which you will learn to format string, number, boolean, date, and time in java.…
Read More Formatting Output with printf() in Javaclass Vehicle { int maxSpeed = 250; public void printMaxSpeed() { System.out.println(“Max speed: ” + maxSpeed); } } class Car extends Vehicle { int maxSpeed = 300; @Override public void printMaxSpeed() { System.out.println(“Max speed: ” + maxSpeed); } } class Test { public static void main(String[] args) { Vehicle vehicle = new Car(); // upcasting…
Read More Upcasting Vs Downcasting in JavaString validation plays a crucial role in Java programming as it helps ensure the correctness and reliability of data processing. Strings are fundamental data types used to store text-based information, such as user inputs, file contents, or database values. However, these strings can often be empty, null, or contain only whitespace characters, which can lead…
Read More Check if a String is Null, Empty or Blank in JavaThis tutorial will teach you how to split a string in Java. There is more than one way to split a string, so we will look at several ways. Let’s start with a very basic one. Split a String To split a string in Java, you can use a String class’s split() method. The split()…
Read More How to Split a String in Java: Different ExamplesIn this tutorial, you will learn how to convert an image byte[] array into a Base64 encoded string of characters. Additionally, you might be interested in checking the “Converting byte[] Array to String in Java” tutorial. Convert Image to a byte[] Array Let’s assume that we have an image on our computer. Our task is to…
Read More Convert Image byte[] Array to Base64 encoded String in JavaThis tutorial will teach you how to convert an array of bytes to a string of characters in Java. Additionally, you might be interested in learning how to convert an image/file byte[] array to a Base64 encoded String. If you are, then check the following tutorial. How to Convert Image byte[] Array to Base64 encoded…
Read More Converting byte[] Array to String in JavaIn this tutorial, you will learn how to round a Float or a Double value to 2 decimal places in Java. 1. Using BigDecimal One of the ways to round a float or a double value is to use BigDecimal class. BigDecimal bigDecimalDouble = new BigDecimal(doubleValue); BigDecimal class allows us to set a scale and…
Read More How to Round Float or Double in JavaThis tutorial will teach you how to convert a String value to an int value in Java. Convert String to int To convert String value to an int value, you can use Integer.parseInt() function. The parseInt() method accepts a String value as a parameter and returns an int value as a result. Successful conversion public…
Read More How to Convert String to int in Java{ “firstName” : “John”, “lastName”: “Doe”, “gender”: “Male”, “state”: “Texas” } public class Person { private String firstName; private String lastName; private String state; // constructors, getters and setters } public class Person { private String firstName; private String lastName; private String gender; <<<< private String state; } import com.fasterxml.jackson.annotation.JsonIgnoreProperties; @JsonIgnoreProperties(ignoreUnknown = true) public class…
Read More Unrecognized field not marked as ignorable – Java JacksonThe @JsonIgnore annotation is used to mark a property or a method that should be ignored by Jackson when serializing or deserializing a Java object to or from JSON. This annotation belongs to the Jackson library, which is a popular library for working with JSON in Java. Spring Boot uses Jackson as the default JSON library,…
Read More @JsonIgnore Annotation in JavaIn this article, we will cover the basics of Aspect-Oriented Programming (AOP). You will learn how to use AspectJ to provide different AOP advices to Spring Boot applications to support cross-cutting issues like logging, profiling, caching, and transaction management and finally we will do a practical implementation to record user operations using Spring Boot AOP.…
Read More A guide to Spring Boot AOP to Record User OperationsIn this tutorial, you will learn how to read data from Dynamo DB using the AWS Lambda function. This tutorial mainly talks about scan and query operations on a DynamoDB table. First, let’s have a quick overview of the DynamoDB table. DynamoDB Table Amazon DynamoDB is a fully managed NoSQL database service that provides fast…
Read More Read Data from DynamoDB using AWS Lambda functiondataType[] arr; Where: int[] intArray = new int[5]; String[] arr = new String[3]; arr[0] = “value 1”; arr[1] = “value 2”; arr[2] = “value 3”;
Read More How to Declare an Array in Java?In this tutorial, you will learn about JUnit5 Lifecycle methods. A Lifecycle Method is any method that is directly annotated or meta-annotated with @BeforeAll, @AfterAll, @BeforeEach, or @AfterEach. Let’s have a look at these annotations one by one. @BeforeAll When a method is annotated with @BeforeAll it means that the method should be executed before…
Read More A Guide to JUnit5 Lifecycle Methods