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In this article, we will learn to make a JTextField accept only numbers in Java. By default, a JTextField can allow numbers, characters, and special characters. Validating user input that is typed into a JTextField can be difficult, especially if the input string must be converted to a numeric value such as an int. Different Approaches The following are the two different approaches for making a JTextField accept only numbers in Java: Using a KeyListener Using DocumentFilter Using a KeyListener The KeyListener interface handles keyboard events, making it straightforward to ... Read More
The dot operator (.) in C++ is a member access operator, which is used to access the members (variables and functions) of a class, structure, and union through an object. It allows you to access and manipulate the properties of an object's data members and member functions. The dot (.) operator is used for various purposes. Here is the following list of its uses. Accessing Data Members Calling Member Functions Working with nested structures /Objects Chained Function Calls ... Read More
In this article, we will learn how to count the number of elements in a stream using the counting() method in Java Streams. Java Streams provide an efficient way to process data collections, and the Collectors.counting() method is useful for counting the number of elements in a stream. The counting() method is a static method of the Collectors class, which is part of the java.util.stream package. It returns a long value representing the number of elements in the stream. Counting the Number of Elements in the Stream The following are the steps to count the number of elements in the ... Read More
A String class can be used to represent character strings; all the string literals in Java programs are implemented as instances of the String Class. In Java, Strings are constants and their values cannot be changed (immutable) once declared.Printing Maximum Occurred Character The maximum occurring character of a string refers to the character that appears multiple times (more than any other character in a string) in a string. To count the maximum occurring character of a string, we have the following approaches - Using an Array Using HashMap Using an Array Using an array is one way to ... Read More
The join() Method In Java, a join() is a final method of the Thread class, and it can be used to join the start of a thread's execution to the end of another thread's execution so that a thread will not start running until another thread has ended. If the join() method is called on a thread instance, the currently running thread will be blocked until the thread instance has finished its execution. The join() method in Java is important in multithreading because it allows one thread to wait for the completion of another thread before continuing execution. Syntax Following is ... Read More
The ArrayList class in Java is a Resizable-array implementation of the List interface. It allows null values. Java clear() Method V/S removeAll() Method There are some important differences between the clear() and removeAll (Collection c) methods of the ArrayList class. This table compares these two methods. Key clear() removeAll() ... Read More
No, HashMap does not allow duplicate keys. The HashMap is a class that implements the Map interface. It is based on the Hash table. It is used to store key-value pairs. It allows null keys and values, but it does not allow duplicate keys. You can store key-value pairs in the HashMap object. Once you do so, you can retrieve the values of the respective keys, but the values we use for keys should be unique. Let's understand what will happen if we try to add a duplicate key into a HashMap.Addng a duplicate key to a HashMapThe put() method ... Read More
The substrings are the sequence of characters that appear within the string. While working with multiple strings, it is useful to find the longest common substring. There are various ways to find the longest common substring from more than two strings. one of the most common approach is using the dynamic programming. Let's dive into the article to learn more about this task. Using Dynamic Programming In this approach, we are going to use the dynamic programming (DP), Here we compare the strings pairwise (starting with first two strings), we find their longest common substring using a DP ... Read More
The Console class is part of the Java.io package and is used to read input from the keyboard or user and write output to the console. Unlike Scanner, the Console class provides methods to read text and passwords. If you read a password using the Console class, it will not be displayed to the user (without showing the typed characters). To use the Console class, we need its object, and the Console object is obtained by calling System.console() as shown below - Console console = System.console(); Note: If you try to execute the program in a non-interactive environment like an IDE, it doesn’t work. It ... Read More
In C++, both dot (.) and arrow (->) operators are used to access members of classes, structures, and unions. But they are used in different scenarios based on how the object is being accessed. In this article, we will learn the differences and uses of these two operators in C++. Dot Operator (.) The dot(.) operator is used to access members (variables and functions) of a class, structure, or union when working with its object (not a pointer). It allows you to access and manipulate the object's properties by directly interacting with members of an object. Syntax Here is the ... Read More