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.toUpperCase(), where ...

Method and variable handles vs. Java reflection To truly understand MethodHandles and VarHandles —what they do and why they are useful—it’s helpful to know a few things about reflection in Java.

To complete the use case, you must convert this one-character String into a single Java char with the charAt(0) method. Java Scanner char input code example The code to get Scanner input one char at a ...