What is System.out.println
System.out.println is a Java statement that prints the argument passed, into the System.out which is generally stdout.

• System – is a final class in java.lang package. As per javadoc, “…Among the facilities provided by the System class are standard input, standard output, and error output streams.[TBD]

• out – is a static member field of System class and is of type PrintStream.

• println – is a method of PrintStream class. println prints the argument passed to the standard console and a newline. There are multiple println methods with different arguments (overloading). Every println makes a call to print method and adds a newline.

Reference
https://javapapers.com/core-java/system-out-println/