How to Check if String contains Substring in Java

Question – How do I check If a String contains another substring in Java? In our previous article, you learned to compare two strings in Java programming language. This tutorial will help you to check if the main string contains another substring in it.

Syntax

str1.contains(str2) // Case sensitive str1.toLowerCase().contains(str2.toLowerCase()) // Ignore case12str1.contains(str2)    // Case sensitivestr1.toLowerCase().contains(str2.toLowerCase())   // Ignore case

Example 1 – Check with Case Sensitive

This will be case sensitive check. As per the below example, Welcome is different than welcome as we know java is a case sensitive programming language.

String str1 = "Hi, Welcome to TecAdmin"; str1.contains("Welcome") //Return True str1.contains("welcome") //Return false (due to case sensitive)1234String str1 = "Hi, Welcome to TecAdmin"; str1.contains("Welcome")   //Return Truestr1.contains("welcome")   //Return false (due to case sensitive)

Example 2 – Check with Ignoring Case

Using this string will be checked with ignoring the case. The function change string to lower case and check if one string contains another case.

String str1 = "Hi, Welcome to TecAdmin"; String str2 = "welcome"; //The below code will change all charecters to lower case //Then compare strings, but do not change original content. str1.toLowerCase().contains(str2.toLowerCase()) //Return true123456String str1 = "Hi, Welcome to TecAdmin";String str2 = "welcome"; //The below code will change all charecters to lower case//Then compare strings, but do not change original content.str1.toLowerCase().contains(str2.toLowerCase())   //Return true