Java

In this post, we will explore string interview programs in java for fresher. Here, The commonly asked simple java string interview programs are listed. The program question is explained and the multiple possible answers are discussed to get different logical view to approach a problematic solution. Strings are an integral part of programming, serving as the cornerstone for manipulating and processing textual data. As a fresher, mastering string manipulation techniques is not only essential for acing technical interviews but also…

In this blog post, we will learn how to use default parameter values in Java. Java has many ways to define default values for parameters in methods. This can help reduce the amount of code we write, and make our code more readable and easier to maintain. What are Default Parameter Values? A default parameter value is a value assigned to a parameter in a method if no value is provided by the calling code. It's a useful feature when…

Random alpha-numeric strings are used in a variety of applications, from generating unique IDs and passwords to creating temporary activation codes and more. In this guide, we will show you how to generate random alpha-numeric strings in Java. Why Use Random Alpha-Numeric Strings Random alpha-numeric strings are important in software development because they provide a way to create unique identifiers that can be used for a variety of purposes. For example, you may need to generate a unique user ID…

JUnit is a popular Java-based testing framework for writing and running tests for applications. In JUnit, you can write tests to ensure that your code behaves as expected, including verifying that exceptions are thrown in the correct circumstances. In this post, we'll cover how to use assertions to confirm that exceptions are thrown in your JUnit tests. Understanding JUnit Assertions Before diving into how to assert exceptions, let's first understand what assertions are in JUnit. In JUnit, an assertion is…

In this post, we'll learn how to create an executable JAR file that contains all the dependencies required to run a Java application using Maven. Maven is a popular build tool that can simplify the process of creating JAR files with dependencies. What is an executable JAR? An executable JAR is a standard Java archive file that can be run directly without the need to extract its contents. It contains the compiled classes, resources, and dependencies of a Java application,…

Sorting arrays before processing them in Java can lead to significant performance improvements in certain situations. This is because sorting an array allows for more efficient processing techniques, such as binary search, to be used. In this post, we will discuss why processing a sorted array is faster than processing an unsorted array in Java. Binary Search One of the main reasons why processing a sorted array is faster in Java is due to the ability to use binary search.…

Java enums are a convenient way to define a set of named constants. However, sometimes we need to convert a string representation of an enum value to its corresponding enum instance. This can be useful in a variety of scenarios, such as parsing user input or reading data from a file. In this post, we will explore several different approaches to converting a string to an enum value in Java. Using the valueOf Method The simplest and most direct way…

Java provides two main classes for implementing a hash table data structure - HashMap and Hashtable. Although they seem similar, there are several key differences between the two that make them appropriate for different use cases. Thread Safety The most significant difference between HashMap and Hashtable is that HashMap is not thread-safe while Hashtable is thread-safe. This means that if multiple threads try to access a HashMap at the same time, there is a possibility of data being corrupted. On…

ArrayList is a popular data structure in Java that provides a dynamic and resizable array, unlike traditional arrays that have a fixed size. ArrayLists are widely used in programming and can be easily converted from an array. In this article, we'll look at the various ways of converting an array into an ArrayList in Java. 1. Using the Arrays.asList Method The Arrays.asList method is the simplest and most straightforward way of converting an array into an ArrayList in Java. The…

In Java, it is often necessary to convert values from one data type to another. One common conversion is converting an integer value to a String. This can be useful when needing to display a numerical value in a text format, or when concatenating multiple values into a single string. In this blog post, we will explore the different methods available to convert an int to a String in Java. 1. Using the valueOf() Method The valueOf() method is a…

In Java, the conversion of a string representation of a date to a java.util.Date object is a common task. In this article, we'll go over the different methods of converting a string to a date and provide code examples for each. 1. SimpleDateFormat The SimpleDateFormat class is a format class that is used to parse and format dates. It takes a string pattern that represents the format of the string representation of a date. To convert a string to a…

Java is an object-oriented programming language that provides various data structures for efficient data storage and manipulation. One of the most commonly used data structures in Java is the List. A List is an ordered collection of elements and can contain duplicate values. There are several ways to create a new List in Java, each with its own advantages and disadvantages. In this post, we'll cover the most commonly used methods for creating lists. 1. Using the ArrayList Class The…

In this post, we will be discussing how to retrieve the current date and time in Java. There are several ways to accomplish this, and we will explore some of the most common methods. 1. Using the Date and Calendar Classes The Java Date class is a data structure that represents a specific moment in time. It includes information such as the year, month, day, hour, minute, second, and time zone. The Calendar class, on the other hand, is an…

A JAR (Java Archive) file is a collection of compiled Java code and other resources that can be executed by the Java Virtual Machine (JVM). The main class in a JAR file is specified in the manifest, a file contained within the JAR. If the main class is not specified in the manifest, you may receive the "no main manifest attribute" error when trying to execute the JAR. Cause of the Error The error occurs when the JAR file does…

JSON (JavaScript Object Notation) is a lightweight data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. JSON is often used to transmit data between a server and a web application, as an alternative to XML. In Java, there are several libraries available for parsing JSON data. In this blog post, we will discuss the most popular and commonly used libraries for parsing JSON in Java. Jackson Library for JSON…

Rounding a number to a specific number of decimal places is a common task in programming, especially when dealing with monetary or financial calculations. In Java, there are several methods that can be used to round a decimal number to a specific number of decimal places. 1. Using the Math.round() method The Math.round() method can be used to round a decimal number to a specific number of decimal places. It returns a rounded long value that is closest to the…

Java is a popular programming language used for developing various applications. However, sometimes, developers encounter certain errors that hinder their progress. One such error is the "java.lang.UnsupportedClassVersionError: Unsupported major.minor version". What is the "Unsupported major.minor version" Error? The "java.lang.UnsupportedClassVersionError: Unsupported major.minor version" error occurs when a Java class has been compiled with a newer version of the Java SDK than the version being used to run it. Causes of the Error There can be several reasons for this error: The…

Java provides access modifiers to control the visibility and accessibility of class members. In this blog post, we'll discuss the differences between four main access modifiers in Java: public, protected, package-private, and private. Public The public access modifier is the most permissive of all access modifiers. A class member declared as public can be accessed from anywhere in the code, regardless of the package it is defined in. public class Example { public int x; public void setX(int x) {…

The sun.security.validator.ValidatorException is a common issue that Java developers may face when working with SSL/TLS connections. This exception is thrown when the certificate validation process fails, and it can occur due to various reasons, such as certificate mismatch, untrusted certificate chains, outdated certificates, and more. In this article, we'll discuss some of the most common causes of the sun.security.validator.ValidatorException and provide step-by-step instructions on how to fix the issue. 1. Verify the Certificate The first step in fixing the sun.security.validator.ValidatorException…

SunCertPathBuilderException is a Java exception that occurs when a certificate chain can't be built up to a trusted root. This error is often encountered while establishing an SSL connection and can be caused by various reasons such as invalid certificates, misconfigured truststore, or missing intermediate certificates. 1. What is SunCertPathBuilderException? SunCertPathBuilderException is an exception class in Java that extends the CertPathBuilderException class. It occurs when the Java runtime environment is unable to build a certificate chain to a trusted root.…