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Articles by Shriansh Kumar
Page 8 of 22
What are the different steps involved to execute a Java program?
Java is an object-oriented programming language that provides various features like platform independence, security, garbage collection, etc. Unlike other programming languages, programs written in Java go through a specific sequence of steps during the compilation and execution process. Java follows the same process no matter where and how you compile and execute Java programs, whether using an IDE or the Command Prompt. In this article, we will discuss and understand the steps Java follows to execute programs. Compilation and Execution Process of Java Program Java program execution follows 5 major steps, which are as follows: Step 1: Edit or ...
Read MoreWhat are the differences between ClassNotFoundException and NoClassDefFoundError in Java?
In Java, both ClassNotFoundException and NoClassDefFoundError are issues that occur when the JVM or ClassLoader is not able to find the appropriate class at the time of loading (run-time). The ClassNotFoundException is a checked exception, and NoClassDefFoundError is an Error that comes under unchecked. There are different types of ClassLoaders, each responsible for loading classes from different sources such as directories, JAR files, or network locations. If a required class is missing due to an incorrect classpath or a missing JAR file, the ClassLoader might fail to load it. This situation leads to one of these two issues. The ClassNotFoundException in ...
Read MoreCan we write any code after throw statement in Java?
No, we can not place any code after throw statement, it leads to compile time error. The compiler will show this error as unreachable statement. In Java, the throw statement immediately terminates the current flow of execution, therefore, the code immediate to a throw statement will not be executed. The control is then transferred to the next catch block or the caller method. The throw Keyword in Java The throw keyword is used to throw an exception manually. Whenever it is required to stop the execution of the functionality based on the user-defined logical error condition, we will use this ...
Read MoreIs it possible to create a class without a name in Java?
Yes, we can create a class without a name in Java using the anonymous class. It is a type of inner class which does not have a name and whose instance is created at the time of the creation of the class itself. You can create this class in a single statement using the new keyword. Creating multiple instances of this class is not allowed. You can use anonymous classes in case where you need to override methods of a class or an interface for a one-time use, and you don't want to create a separate named class for it. ...
Read MoreWhy String class is immutable or final in Java?
The general meaning of immutable is something that cannot be changed or modified after creation. In Java, a string is immutable; we cannot change the object itself, but we can change the reference to the object. The string is made final to not allow others to extend and modify it. When you modify a string, a new copy of the string with your modifications is created. This article will explain what a String is and why it is immutable and final in Java. What is a String? Like other object-oriented programming languages, almost every component of Java is an object, ...
Read MoreHow to solve an IllegalArgumentException in Java?
In Java, an IllegalArgumentException is thrown in order to indicate that a method has been passed an illegal argument. An illegal argument is one that does not meet the required input from user. This exception extends the RuntimeException class and thus, belongs to those exceptions that can be thrown during the operation of the Java Virtual Machine (JVM). It is an unchecked exception and thus, it does not need to be declared in a method's or a constructor's throws clause. Reasons for java.lang.IllegalArgumentException Some of the reasons for IllegalArgumentException in Java is as follows: ...
Read MoreCovariant return types in Java
In Java, covariant return types allow an overriding method to return a subtype of the supertype. Here, the return type of the parent class is called the supertype, and the return type of the child class is known as the subtype, if and only if it is a subclass of the parent class's return type. Sounds confusing, right? Well! It is not as confusing as it sounds. Read the whole article to understand this concept. Java Covariant Return Types Covariant return type refers to the return type of an overriding method. It works only for non-primitive return types, such as Classes, Arrays, ...
Read MoreDowncasting in Java
What is Downcasting? Typecasting an object of the parent class to an object of the child class is called Downcasting in Java. We need to tell the Java compiler to perform the conversion explicitly by creating an object of the child type using a reference of the parent type. It is the opposite of upcasting, where a subclass reference is converted into a superclass reference automatically by the compiler. Typecasting is a process in which one data type or object is converted into another. It works with primitive datatypes and reference types as well. In this article, we are going ...
Read MoreInterface enhancements in Java 8
Before the release of Java version 8, the interface consists of only abstract methods and variables that defines the behavior that a class could implement. While adding a new method to an interface, it required change in all the implementing classes. It was not convenient for a large application. To overcome this, Java 8 introduced default and static methods in interfaces. In Java, an Interface is a type of class that is defined using the keyword interface and has only method bodies without any implementations. To access its members within a class, we need to use the implements keyword while ...
Read MoreHow to compile & run a Java program using Command Prompt?
Command prompt is a command line interface that accepts text-based inputs or commands and performs tasks based on those command. Nowadays, there are various integrated development environments (IDEs) that are available to compile, build, and run Java programs within their environment. However, we can also compile and run Java programs using the Command Prompt. Compiling and Running Java Programs using CLI To compile and run Java programs outside the IDEs using the Command Prompt, we need to install the JDK and set its path in our system. To set up the development environment for Java on your local machine, we ...
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