String is widely used as a parameter for many java classes, e.g. network connection, opening files, etc. Were String not immutable, a connection or file would be changed and this can lead to a serious ...

System.out.println(str.toUpperCase()); System.out.println(str); //Print the string in uppercase System.out.println(str.toLowerCase()); //Print the string in lowercase /* * String is immutable in Java.