Behind the scenes, when you write String::toUpperCase, Java binds each element of the stream (String object) to the toUpperCase() method. This means String::toUpperCase is interpreted as s -> s ...

Useful for Utility Methods. #Java Standard Library Methods JSL provides a vast collection of pre-defined classes and methods organized into packages. a. java.lang Package -> automatically imported, ...

At this point, the Scanner still returns a String, although the String contains only one character. To complete the use case, you must convert this one-character String into a single Java char with ...