java

Who doesn't know "Hello, World!"? When you start writing a code in a new language, you usually write this simple program. What does it look like in Java code? class App { public static void main(String[] args) { System.out.println("Hello, World!"); } } But, explain to a beginner what "public static void" and strange args are. What would you say if the program could be simplified. class App { void main() { System.out.println("Hello, World!"); } } Let's make it even simpler, without class declaration. void main() { System.out.println("Hello, World!"); } Yes, this is simplest Java code in Java 21 release. Try it yourself. In a Java 21 preview feature (JEP 445) it needs to be enabled by with the --enable-preview flag. Just compile your application by command javac --release 21 --enable-preview App.java and run it as simple as java --enable-preview App This simplification i

Is flase true? Or true is false... Let's find out together.

Will this Java code run? The Test instance variable via the value() method returns null.  What about NullPointerException? Is it possible to access the pi member through null?