String 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 JavaI hope you find these video lessons helpful. There are many more video lessons that I have recorded and packaged into a single video course. Please check out my video course below if you want to learn how to do Unit Testing and Integration Testing of Java applications.
Read More Unit Testing Java Video Tutorials{ “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 JavadataType[] 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 Unit Testing AWS Lambda Function with Java. First, we will have a quick overview of Unit Testing. Then we will look at the required dependencies in order to do Unit Testing of AWS Lambda Function. After that, we will dive deep into the annotations that will be used…
Read More Unit Testing AWS Lambda Function with Javasynchronized void method() {} public class SynchronizedInstanceMethodExample implements Runnable { public static void main(String[] args) { SynchronizedInstanceMethodExample runnable = new SynchronizedInstanceMethodExample(); new Thread(runnable).start(); // creates one thread new Thread(runnable).start(); // creates second thread } // Inherited run method from the Runnable interface @Override public void run() { try { // Calling the non-synchronized method print()…
Read More Java Synchronized Blocks and Methodsclass PrintArrayElementsExample { public static void main(String[] args) { int[] arr1 = {1, 7, 9, 5, 2, 8, 3}; String[] arr2 = {“Megan”, “Tom”, “Melissa”, “John”, “Steve”}; // print elements of the arr1 System.out.println(Arrays.toString(arr1)); // print elements of the arr2 System.out.println(Arrays.toString(arr2)); } } Output: [1, 7, 9, 5, 2, 8, 3] [Megan, Tom, Melissa, John,…
Read More Print Array Elements in Javapublic class SplitString { public static void main(String[] args) { String names = “Tom,Steve,John,Megan,Melissa”; // split string String[] arr = names.split(“,”); // print the size of the array System.out.println(arr.length); // print the elements Stream.of(arr).forEach(System.out::println); } } Output: 5 Tom Steve John Megan Melissa If you need a list, instead of an array, use the…
Read More Split a comma-separated String in JavaIn this tutorial, you will learn how to implement the API Gateway Lambda Authorizer in Java. You will also learn how to make Lambda Authorizer validate Authorization JWT. First, we will create an API using API Gateway then we will make lambda function as an integration point for the GET method of our resource. After…
Read More API Gateway Lambda Authorizer Example in Java