The Java Date class keeps track of those milliseconds as a long value. Because long is a signed number, dates can be expressed before and after the start of January 1, 1970.

Find out how the Java Date and Time API addresses the need for a more robust date and time infrastructure in Java SE, then familiarize yourself with the java.time classes you're most likely to use ...

The java.util.Scanner import statement at the top of many Java classes means that somewhere in the code, the Scanner class is being used. Java user input made easy; ... and also avoid possible import ...