Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Java Articles
Page 156 of 450
Why do we get ClassNotFoundException when the class exists in Java?
Whenever we try to load a class, ClassNotFoundException occurs when the application tries to load a class at runtime using methods like Class.forName() or ClassLoader.loadClass(), but the JVM cannot locate the class in the classpath. The following are the reasons of ClassNotFoundException occurence and they are - Incorrect Class Name Incorrect Package Structure ...
Read MoreHow to change/increase the heap size of the Java Virtual Machine in Java?
A Java program can execute in the Java Virtual Machine (JVM) and uses the heap memory to manage the data. If our Java program requires more memory, there is a possibility that the Java Virtual Machine(JVM) will begin to throw OutOfMemoryError instances when attempting to instantiate an object in Java. How to change/increase the JVM Heap Size? In Java, it is possible to increase the heap size allocated by the JVM: -Xms: Set an initial Java heap size JVM automatically manages the heap memory but we can ...
Read MoreCan we change method signature in overriding in Java?
No, you cannot change the method signature while overriding. Changing the method signature becomes method overloading, not overriding. Now, let's understand why - Method Signature In Java, a method signature consists of - Method name: It is used to call the method. Parameter list: It includes the number, type, and order of parameters. Note: The method signature does not include return type, ...
Read MoreDifference between constants and final variables in Java?
In Java, both constants and final variables are used to define variables that cannot be changed after initialization. But they have some differences. In this article, we will learn how they are different. Final Variable A final variable in Java means you cannot reassign it after it has been initialized. Whether it is a local variable, instance variable, or static variable, once it's assigned, the value cannot be changed. If you try to do so, a compile-time error will be generated. public class FinalExample { public static void main(String args[]) { ...
Read MoreIs Swing thread-safe in Java?
No, Java Swing components are not thread-safe in Java. This means that whenever Swing components should be accessed or changed, it is done mostly by using a single thread, the EDT. Why Swing Components are not thread-safe One of the main reasons Java Swing is not thread-safe is to simplify the task of extending its components. Another reason for that Java Swing is not thread-safe due to the overhead involved in obtaining and releasing locks and restoring the state. Below are some methods given by Swing for safe operation with its UI: SwingUtilities.invokeLater(): In ...
Read MoreHow to get all the keys of a JSON object using GSON in Java?
JSON is the data interchange format that stores values in key-value pairs. (To learn more about JSON, you can refer to the JSON tutorial). So, as we have key and value in JSON, we will try to get all those keys using the Gson library. Gson Library:Â Retrieving all the keys of a JSON Gson is a third-party Java library developed by Google. It is used for converting Java objects to JSON and vice versa. To know more about Gson, refer to the Gson tutorial. We can use the keySet() method of JsonObject class to get all the keys of a ...
Read MoreWhat are the differences between the TableCellRenderer and TableCellEditor in Java?
In this article, we will learn about the differences between the TableCellRenderer and TableCellEditor in Java. The JTable interface in Java Swing has these important interfaces called TableCellRenderer and TableCellEditor. Though they serve different purposes, they complement each other in defining the table cells' render and edit functions. TableCellRenderer A TableCellRenderer creates a component that displays the value of a JTable cell. The default renderer uses JLabel to display the value of each table cell. The TableCellRenderer interface can be specified in three ways : By the class of the object to be ...
Read MoreWhat is the importance of JSeparator class in Java?
In this article, we will learn about the importance of the JSeparator class in Java. In GUI programming, appearance is highly important in creating good and user-friendly Java programs. Java Swing provides the JSeparator class as a simple but effective means of accomplishing this. What is JSeparator? A JSeparator is a horizontal or vertical line or an empty area used to split the components. A class called JSeparator is used to paint a line in order to divide the components within a Layout. The simplest way to insert a separator into a menu or a toolbar is by invoking the ...
Read MoreWhat are the differences between a JTextPane and a JEditorPane in Java?
In Java, a JTextPane is an extension of JEditorPane which provides word processing features like fonts, text styles, colors and etc. If we need to do heavy-duty text processing, we can use this class, whereas a JEditorPane supports display/editing of HTML and RTF content and can be extended by creating our own EditorKit. JTextPane A JTextPane is a subclass of JEditorPane. A JTextPane is used for a styled document with embedded images and components. A JTextPane is a text component that can be marked up with the attributes that are represented graphically and it can use a DefaultStyledDocument as the ...
Read MoreHow can we parse a nested JSON object in Java?
Sometimes, we need to parse a nested JSON object, which means an object inside another object. In this article, let's learn about how to parse a nested JSON object in Java. If you don't know about JSON, refer JSON overview. Parsing a Nested JSON Object in Java? We can achieve this using some of the popular Java libraries. Those are listed below: Using org.json library : We will use jsonObject.getJSONObject method to parse a nested JSON object. Using Gson library : We will use JsonParser.parseString(json).getAsJsonObject(). Using Jackson library : In this, We will use ObjectMapper.readTree(json) method. Now, ...
Read More