The release of Java SE 15 in Sept 2020 will introduce "sealed classes" (JEP 360) as a preview feature. A sealed class is a class or interface which restricts which other classes or interfaces may ...

Although the snooze button is probably the most commonly used button on an alarm clock, even a simple AlarmClock class needs a few more features. For instance, you might want to control how long the ...

Java’s String class encapsulates an array of bytes. A byte can be converted to a char, in which case, String becomes an array of characters used to compose words, sentences, or any other data you want ...