public class APITester {

   public static void main(String[] args) {
      String stringJSON = "{\r\n" 
         + "\"Name\" : \"Mahesh\",\r\n" 
         + "\"RollNO\" : \"32\"\r\n" 
         + "}";  

      System.out.println(stringJSON);

      String textBlockJSON = """
         {
            "name" : "Mahesh",
            "RollNO" : "32"
         }
         """;
      System.out.println(textBlockJSON);

      System.out.println("Contains: " + textBlockJSON.contains("Mahesh"));
      System.out.println("indexOf: " + textBlockJSON.indexOf("Mahesh"));
      System.out.println("Length: " + textBlockJSON.length());
   }   
}

$javac -Xlint:preview --enable-preview -source 13 APITester.java

$java --enable-preview APITester

{
"Name" : "Mahesh",
"RollNO" : "32"
}
{
   "name" : "Mahesh",
   "RollNO" : "32"
}

Contains: true
indexOf: 15
Length: 45