tolowercase java

String txt = "111 World";
System.out.println(txt.toUpperCase());
System.out.println(txt.toLowerCase());

String s1 = "JAVATPOINT HELLO stRIng";  
String s1lower = s1.toLowerCase(); // s1lower = "javatpoint hello string" 

String txt = "123 World";
System.out.println(txt.toUpperCase());
System.out.println(txt.toLowerCase());