Check if a String contains another String in Java

Core Java classes provide different solutions that developers can use to check if a String contains another String inside it. In this article we will show you different Java code examples how to check if a String is inside another String using core Java methods such as String.contains(), String.indexOf(), String.lastIndexOf(), String.matches() and java.util.regex.Pattern class.

Replace or Remove All Digits of a String in Java using regular expression

In this article we are going to learn how to use core Java classes to remove all numeric characters from a String or replace numeric characters with other characters. We will show you different Java code examples how to use String.replaceAll() method and java.util.regex.Pattern class.

Extract Digits from a String in Java using regular expression

In this post we show you how to use regular expressions to remove all non-digits characters of a String and return the number only String in Java application.