Java Tutorial

This example will tell you how to check whether a year is a leap year or not. As we know, leap year is an integer that can be divided by 4 but can not be divided by 100. For example, 1996 is just a leap year while 1900 is not. But if a year can […]

The java.lang.System‘s out and err objects are used to write text data to the standard output stream and standard error stream. The default output stream is the command-line console. But the java.lang.System class also provides a method for you to redirect the standard output stream to other destinations such as file stream. With this, you

This example will tell you how to use java standard input, output, and error object to read string data from user command line input, write string data to standard output console and display error messages to standard error output. All the standard input or output object is the static variable of java.lang.System class.

This example show you how to check if a string content is numeric or not. It provide totally six methods to use. package com.dev2qa.calculatorexample; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * Created by zhaosong on 2018/5/23. */ public class CheckStringNumeric { public static void main(String args[]) { CheckStringNumeric checkStringNumeric = new CheckStringNumeric(); checkStringNumeric.isNumeric(“-123.45”); checkStringNumeric.isInteger(“-123”); checkStringNumeric.isIntegerByParse(“-123.456”); checkStringNumeric.isDoubleByParse(“-123.456789”);

This example include java code to check whether a given www domain or a host name string is a valid domain or not. You can see code comments for detail explanation.