JShell on foojay.io - Friends Of OpenJDK

Live (re)compile, (re)load, (re)execute Java code in 100 LoC

Wed, 15 Nov 2023 16:22:05 +0000

Writing your first program in Java can have quite a learning curve.

Java has been trying in recent releases to make it easier to write the first simple program.

Here are some changes that simplify your first Java program:

JEP 222: jshell: The Java Shell (Read-Eval-Print Loop) in JDK 9
JEP 330: Launch Single-File Source-Code Programs in JDK 11
JEP 445: Unnamed Classes and Instance Main Methods in preview in JDK 21
JEP 458: Launch Multi-File Source-Code Programs. Not released yet.

In this article, we’ll write a program (The Reloader) to easily play with Java code without the need to know how to compile or run the code or print the result.

Schedule your 2038 holiday and experiment with dates in jshell!

Thu, 16 Feb 2023 15:54:51 +0000

It’s still more or less the beginning of the year, where you may want to start scheduling your holidays until the end of it. And I decided to go a step further and I’ve already planned those for 2038!

Why? Well, some time ago I gave a presentation to students, when I realized they had no idea what I was talking about when mentioning the Y2K-problem. Most of them weren’t even born in the year 2000!

Hand Ground Coffee: Command Line Tools for Java

Mon, 21 Feb 2022 16:04:15 +0000

In the book “97 Things every Java Programmer should know” (I contributed 2 of the 97 tips) there is a chapter about some command line tools in the JDK.

Since I make heavy use of such helpers myself, I wanted to briefly introduce them in today’s article.

Personally I prefer the command line for my daily work, using the combination of git, sed, grep, bash commands etc. makes recurring tasks easier.

Learn JShell with JavaFX in Only 60 Seconds

Mon, 12 Jul 2021 10:54:56 +0000

Spoon boy : Do not try and bend the spoon. That’s impossible. Instead… only try to realize the truth.
Neo : What truth?
Spoon boy : There is no spoon.
Neo : There is no spoon?
Spoon boy : Then you’ll see, that it is not the spoon that bends, it is only yourself.

– The Matrix, a conversation between Neo and Spoon boy.

In the classic science fiction movie, The Matrix, there’s a cool special effect better known as the falling or raining green code effect. In one scene the character named ‘Cypher’ played by Joe Pantoliano explains how they can monitor activity inside the matrix by looking at the patterns as the code rains down. He claims it’s done this way to simplify seeing people in the matrix than other means due to the fact that there is just way too much data (movie scifi magic talk).