Programming Articles - Page 2091 of 3363

JShell is a new concept introduced in Java 9 version. It provides Java with REPL (Read-Eval-Print-Loop) ability. By using JShell, we can test the java-based logic and expressions without compiling it. REPL acts as an immediate feedback loop and has a great effect on productivity in that particular language.Step 1: Open Command Prompt and type JShell.Microsoft Windows [Version 6.3.9600] (c) 2013 Microsoft Corporation. All rights reserved. C:\Users\User>JShell | Welcome to JShell -- Version 9.0.4 | For an introduction type: /help intro jshell>Step 2: Type /help (to view JShell commands) in the JShell command window once it starts running.jshell> /help | Type ... Read More

There are two new parameters or attributes added to @Deprecated annotation in Java 9. Those parameters are Since and forRemoval, both of these two parameters are optional with a default value when we can't specify it.SinceThis string parameter specifies the version in which the API became deprecated. The default value of this element is an empty string.Syntax@Deprecated(since="")forRemovalThis boolean parameter specifies whether the API is intended to be removed in a future release or not. The default value is false when we can't specify it.Syntax@Deprecated(forRemoval=)Examplepublic class DeprecatedAnnotationTest {    public static void main(String[] args) {       DeprecatedAnnotationTest test = new DeprecatedAnnotationTest();       test.method1();   ... Read More

CompletableFuture API is used for asynchronous programming in Java. It means that we can write non-blocking code by running a task on a separate thread than the main() thread and notify the main() thread about its progress, completion or failure. Java 9 introduces a few improvements in CompletableFuture API,  they are: "Support for timeouts and delays", "Improved support for subclassing" and "Addition of new factory methods".Support for timeouts and delayspublic CompletableFuture orTimeout(long timeout, TimeUnit unit) The above method has been used to specify if the task does not complete within a certain period of time the program stops and throws TimeoutException.public CompletableFuture completeOnTimeout(T value, long timeout, ... Read More

The CSV file or comma separated values file are one of the most widely used flat files to store and hare data across platforms. The columns are separated by comma and there is optional header row also which will indicate the name of each column. Python can read the CSV files using many modules. In this article we will see how the CSV library in python can be used to read and write a CSV file. We can also see the pandas library onl to read the CSV file.Reading CSV file using csv moduleWe can get the CSV file from ... Read More

Python language is used extensively for web programming. When we browser website we use the web address which is also known as URL or uniform resource locator. Python has inbuilt materials which can handle the calls to the URL as well as pass the result that comes out of visiting the URL. In this article we will see a module named as urllib. We will also see the various functions present in this module which help in getting the result from the URL.Installing urllibTo install urllib in the python environment, we use the below command using pip.pip install urllibRunning the ... Read More

Sentiment Analysis is the process of estimating the sentiment of people who give feedback to certain event either through written text or through oral communication. Of course the oral communication also has to be converted to written text so that it can be analysed through python program. The sentiment expressed by people may be positive or negative. By assigning weightage to the different words in the sentiment text we calculate a numeric value and that gives us a mathematical evaluation of the sentiment.UsefulnessCustomer Fedback − It is vital for business to know the customer’s opinion about product or services. When ... Read More

In Python deque is a data structure like stack and queue. It allows append and pop operations from both the ends of the queue. And that makes it different from the rest of the data structures. There are various operations which are listed below that is applicable to deque. In this article we will see the examples on each of those operations. The collections module is used to implement deque.Deque OperationsBelow are some of the useful operations carried out using dequeappend() − This function is used to insert the value in its argument to the right end of deque.appendleft() − ... Read More

As part of data processing activity we sometimes need to append one string with another. In this article we will see how to append dynamic number of zeros to a given string. This can be done by using various string functions as shown in the programs below.Using ljust and lenPython string method ljust() returns the string left justified in a string of length width. Padding is done using the specified fillchar (default is a space). The len() returns the length of the string. We add trailing zeros to the string by manipulating the length of the given string and the ... Read More

The @SafeVarargs annotation was introduced in Java 7. This annotation applies to both final and static methods or constructors that take varargs parameters. This annotation used to make sure that a method does not perform unsafe operations on its varargs parameters. Since Java 9, @SafeVarargs annotation also applies to private instance methods.Syntax@SafeVarargs private void methodName(...) {    // some statements }Exampleimport java.util.ArrayList; import java.util.List; public class SafevarargsTest {    @SafeVarargs     // Apply @SafeVarargs to private methods    private void display(List... names) {       for(List name : names) {          System.out.println(name);       }    }    public static void ... Read More

In earlier versions of Java, the underscore ("_") has used as an identifier or to create a variable name. Since Java 9, the underscore character is a reserved keyword and can't be used as an identifier or variable name. If we use a single underscore character as an identifier, the program fails to compile and throws a compile-time error because now it is a keyword and can't be used as a variable name in Java 9 or later versions.Examplepublic class UnderscoreKeywordTest {    public static void main(String args[]) {       int _ = 50       System.out.println(_);   ... Read More