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 ...

Many programming languages, including Java, typically associate round brackets or parentheses with methods. The parameter list for a method is always placed in round brackets in Java: public void ...

Using Java’s String length method. To get the number of characters in a given piece of text, the Java String length() method is all you need. Just make sure the String is not null, and avoid any ...