how to check if a character is present in a substring of a given string in java code example

Example 1: java if string contains character

if (string.contains(character)

Example 2: string check if substring exists java

String str1 = "Java";
String str2 = "va";

if(str1.contains(str2)){
  // str1.contains(str2) will be true here.
  System.out.println("I am true");
}