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Articles by Shriansh Kumar
Page 5 of 22
What are the differences between the Heap memory and the String Constant Pool in Java?\\n
The Heap Memory and String Constant Pool are two different memory locations in Java where objects are stored during the execution of programs. Both memory areas are managed by the Java Virtual Machine. In this article, we are going to discuss the difference between Heap Memory and String Constant Pool in Java. Heap Memory Heap memory is a runtime data area from which memory for all class instances and arrays is allocated. It is the main memory area used for dynamic memory allocation in Java. Example Creating strings with the new keyword always allocates new memory in the heap. In ...
Read MoreCan we declare more than one class in a single Java program?\\n
Declaring Multiple Classes in Java Program A single Java program may contain two or more classes, it is possible in two ways: Multiple non-nested classes Nested classes The Multiple non-nested Classes We can create as many classes as we want in a single Java program but writing many classes in a single file is not recommended as it makes code difficult to read rather we can create a single file for every class. When we compile a Java program with two or more classes (non-nested), the same number of .class ...
Read MoreWhat are unreachable catch blocks in Java?
A block of statements that the program control can never reach under any circumstances can be called an unreachable block. Java does not support unreachable blocks, such code will cause a compile-time error. Any code that is written but never executed is considered unnecessary by the Java compiler. In this article, we will discuss unreachable catch blocks in Java. But, before that, let's understand what is a catch-block in Java. The catch Block in Java The catch block is written just after the try block and cannot have any code between them. It is an exception handler and contains code ...
Read MoreWhy Char[] array is more secure (store sensitive data) than String in Java?
Both String class and Char[] array in Java are used to store textual data. However, Strings are immutable, which means you can't make changes to a String once defined, and the char[] array is not immutable. In the official documentation of Java Cryptography Architecture, it is clearly written that String objects are not suitable for storing sensitive data, such as passwords, SSN, etc. Use a char array instead, as it is more secure than String. This article will help you understand why char[] array is used to store sensitive data. Char Array is more secure than String Let's discuss why ...
Read MoreWhat are the differences between import and static import statements in Java?
The import statement is used to bring certain classes and interfaces from other packages into our Java program, so we can access them without using their fully qualified names. We can use the short name instead. Java also supports static import statements, which were introduced in Java 5. It helps in accessing static members such as methods and constants. In this article, we are going to learn the difference between import and static import statements in Java. The import Statement in Java To access a class or method from another package, we need to either use the fully qualified ...
Read MoreWhat are the differences between Widening Casting (Implicit) and Narrowing Casting (Explicit) in Java?
A Type casting in Java is used to convert objects or variables from one data type to another. When we are converting or assigning one data type to another, automatic conversion will take place (if the types are compatible and the conversion is safe). However, if there is a risk of data loss, the conversion must be done explicitly by the programmer. Let's understand the types of Java type casting and the difference between them in this article. Types of Type Casting in Java Java Type Casting is classified into two types, which are: ...
Read MoreHow to resolve a NullPointerException in Java?
The NullPointerException is a subclass of the RuntimeException class. It is defined in java.lang package of Java. In this article, we are going to understand the reasons for NullPointerException and how to resolve them. Reason for NullPointerException in Java A NullPointerException is a runtime exception thrown by the JVM when our application code, another referenced API, or the middleware encounters the following conditions: Attempting to invoke an instance method of a null object. ...
Read MoreWhy String literal is stored in String Constant Pool in Java?
In Java, the string literals (or, string objects) are stored in a separate memory area called string constant pool to improve the performance of string operations and optimize the memory while using them. Let's understand how. Creating String Objects in Java There are two ways to create a String object in Java: Using the new operator Using String literal Example The example given below shows how to create a string object: public class Example { public static void main(String[] args) { ...
Read MoreWhat 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?\\n
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 ...
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