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Java Articles
Page 154 of 450
How can we disable cut, copy and paste functionality of a JTextArea in Java?
In this article, we will learn to disable the cut, copy, and paste functionality of a JTextArea in Java. While developing Java Swing applications, you may need a situation where you want to restrict user input to text components. Cutting, copying, and pasting is usually needed to be disabled for a JTextArea such that users are not allowed to modify or copy its content. What is a JTextArea? A JTextArea is a subclass of the JTextComponent class, and it is a multi-line text component to display text or allow a user to enter text. A JTextArea can generate a CaretListener interface ...
Read MoreFind the number that appears once, and the other numbers twice in Java
In this problem, we are given an array of integers. In the given array, each element occurs two times except one element, which occurs only once. We have to find the number that appears only once. In this article, we are going to learn how we can find the number that appears once, and all other numbers appear twice in Java. Scenario 1 All other numbers except 4 occur twice, so 4 is the only number that appears only once. Input: [ 1, 2, 3, 3, 2, 4, 1, 5, 5] Output: 4 Scenario 2 All other numbers except ...
Read MoreWhat are the differences between GridLayout and GridBagLayout in Java?
In Java, a GridLayout puts all the components in a rectangular grid and is divided into equal-sized rectangles, and each component is placed inside a rectangle whereas GridBagLayout is a flexible layout manager that aligns the components vertically and horizontally without requiring that the components be of the same size. Java GridLayout A GridLayout arranges the components in a rectangular grid. It arranges components in the cells, and each cell has the same size. Components are placed in columns and rows. GridLayout(int rows, int columns) takes two parameters that are a column and a row. Syntax The following is the ...
Read MoreHow to create a custom unchecked exception in Java?
In Java, the exceptions are of two types: checked and unchecked exceptions. A checked exception is an exception that occurs at compile time; these are also called compile-time exceptions. An unchecked exception occurs at the time of execution. These are also called Runtime Exceptions. In this article, we will learn to create a custom unchecked exception in Java. We can create a custom unchecked exception by extending the RuntimeException class in Java. What are unchecked exceptions? The unchecked exceptions inherit from the Error class or the RuntimeException class. Many programmers feel that we cannot handle these exceptions in our programs because they represent the type of errors ...
Read MoreHow can we implement a JLabel text with different color and font in Java?
In this article, we will learn to implement a JLabel text with different colors and fonts in Java. JLabel is commonly used for simple text display, it can be enhanced to show text with multiple colors and fonts. JLabel A JLabel class can extend the JComponent class, and an object of JLabel provides text instructions or information on a GUI. A JLabel can display a single line of read-only text, an image, or both text and an image. A JLabel can explicitly generate a PropertyChangeListener interface. Different Approaches The following are the two different approaches to implementing a JLabel text ...
Read MoreHow to change each column width of a JTable in Java?
In this article, we will learn to change each column width of a JTable in Java. JTable is Swing's strongest component for displaying and editing tabular information. Adjusting column widths appropriately to display content is among the most prevalent needs for customization. JTable A JTable is a subclass of JComponent for displaying complex data structures. A JTable can follow the Model View Controller (MVC) design pattern for displaying the data in rows and columns. The DefaultTableModel class can extend AbstractTableModel and it can be used to add the rows and columns to a JTable dynamically. Syntax The following is ...
Read MoreWhat are the differences between a Font and a FontMetrics in Java?
The Font class in Java is responsible for setting screen fonts, which are mapped to characters of the language in specific regions. But a FontMetrics class is said to be a font metrics object that encapsulates the data about the rendering of a specific font on a particular screen. Font A Font class can be used to create an instance of a Font object to set the font for drawing text, labels, text fields, buttons, etc, and it can be specified by its name, style, and size. Syntax The following is the syntax for Font initialization: Font font = new ...
Read MoreHow to center align the items of a JComboBox in Java?
In this article, we will learn to center-align the items of a JComboBox in Java. The default rendering of a JComboBox uses a JLabel for each item. JLabel's default alignment is left-justified, hence the misalignment. JComboBox A JComboBox is a subclass of the JComponent class, and it is a combination of a text field and a drop-down list from which the user can choose a value. A JComboBox can generate an ActionListener, ChangeListener, and an ItemListener when the user actions with a combo box. Center-Align the Items of a JComboBox By default, items in the JCombobox are left-aligned. We ...
Read MoreHow can we display the line numbers inside a JTextArea in Java?
In this article, we will learn to display the line numbers inside a JTextArea in Java. When using text editors or code viewers in Java Swing applications, the showing of line numbers can greatly improve the user experience. What is a JTextArea? A JTextArea is a subclass of JTextComponent and it is a multi-line text component to display the text or allow the user to enter a text. A JTextArea can generate a CaretListener interface, which can listen to caret update events. Syntax The following is the syntax for JTextArea initialization: JTextArea textArea = new JTextArea(); By default, JTextArea does ...
Read MoreHow to convert a List to JSON array using the Jackson library in Java?
JSON is used in Java applications in APIs, file storage, and data communication between systems. Sometimes, we need to convert a list into a JSON array. In this article, we will learn how to convert a list to JSON array using the Jackson library. Jackson Library It is a library that is used in Java to work with JSON data. It provides APIs to serialize Java objects into JSON and deserialize JSON back into Java objects. If you want to read more about the Jackson library, you can refer Jackson library. There are mainly three components of Jackson - ...
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