JDK 23 is the latest release of the Java Platform

JDK 23 reached GA on September 2024 and its scope is covered in JSR398. The expert group included experts from Red Hat, Azul, SAP. Oracle and the Eclipse Foundation. The Windows version is only available in 64 bit.

JDK23 introduces the Third Preview for Structured Concurrency whose idea is to simplify concurrent programming incorporating ideas from Erlang (such as hierarchical supervisors).

Groups of related tasks in different threads are treated as a single unit of work, streamlining error handling and cancellation. 

The term Structured Concurrency was coined by Martin Sustrik and popularized by Nathaniel J Smith.

Adding External Jars (aka "Archives") to an Eclipse Project

Suppose you need to include some external libraries in your Java build path. Right click the project, click on Build Path and then "Add External Archives". Presumably you've created a directory in your project folder that holds all these external JARs.

Eclipse Is Great

Eclipse is a great Java IDE that must be celebrated. Among the cool features:

1. Automatic strikethough of class names where the class is deprecated

Eclipse RCP

There is a slew of awesome commercial RCP applications available, check out the online application inventory. Among them is SpiderMonkey for online SEC filings.

Here is a tutorial to get started (by Ed Burnette).

Eclipse Jargon Revealed

Any user of Eclipse is exposed to a vast amount of jargon. This is a quick guide to decrypting this jargon.

BIRT - an Eclipse-based reporting system for web applications. Birt stands for Business Intelligence and Reporting Tools. Here are some examples including a Camtasia studio screencast. (Lotus produced some of the earliest screencasting software in 1994).

Java and Eclipse Shortcuts

Eclipse

Cntrl-Shift-T find Type

Cntrl-L Goto line
Cntrl-B Build

F3 jump to definition

Alt-Enter - File properties (file path, size, file encoding)

Set up different workspaces for "test projects" versus "real projects".

Configuring Eclipse to reference Existing Code

1. Set up a new workspace (different from the source location)
2. use the existing location for the code
3. create projects for specific parts of the code you want to change

Select "autoconfigure JRE and project layout based on source".

Switching Tabs in Eclipse

Control-Tab in Windows applications is replaced by ALT-LEFT and ALT-RIGHT, and Control-F6. Since control-tab is used so frequently it is easy to forget this Eclipse peculiarity.

To override this shortcut, do Windows->Preferences->General->Keys. Then replace "Change Next Editor" from Control-F6 to Control-tab. Sanity at last.

Cntrl-E is another useful way to bring up "Editor List" that allows explicit window switching.

Java

javap -c Disassemble a class file

Navigating Ganymede using Awesome Child-Oriented Fonts like Comic Sans - Makes Reading Java More Fun!

Making your way around Eclipse ain't easy when you're used to MSVC-style GUIs, so here's a primer on how to get things configured double-speedy in the old Ganymede release of Eclipse.

Change Font Size. This should not be difficult but for first-timers it's a super-sized sudoku puzzle.

Windows->Preferences->General->Appearance->Colors and Fonts. Click on the right category e.g. Java editor text font. Set a good font and size. Changing your font regularly keeps code-reading interesting.

• Jokeman is a fun font to liven up boring code.
• Kartika9 is very clear and well-spaced.
• Vivaldi is beautiful and elegant but suffers from lack of readability.
• Mistral makes Java look beautiful.
• ComicSansMS is a nice, friendly readable font, classified as "casual, non-connecting script", a "child-oriented font" in the words of its inventor, Vincent Connare, who designed it for children's software. To quote an esteemed computer philosophe, "The real art of discovery consists not in finding new programming languages, but in seeing with new fonts".
• Gill Sans MT is another "soft font" described as a "humanist" font, created by Eric Gill in 1927 and very popular in logos for media companies (e.g. BBC). Eric Gill received the accolade "Royal Designer for Industry" (Gill9 looks fine).

Show Line Numbers: W->P->G->Editors->Text Editors->Show line numbers

How does Eclipse build Java code?

Eclipse has its own Java compiler (the Eclipse Compiler for Java) that implements the Java Language Specification.

Compliance level can be checked using Alt-WP and clicking Java->Compiler.

Compiler->Errors and Warnings allows you to fine-tune what the compiler regards as error versus a warning. e.g. in my setup: non-static access to a static member is a warning, undocumented empty block is ignored.

The compiler is part of the JDT (Java development tools) extension to the workbench. It is not possible to use another Java compiler other than the built-in one (which includes support for special features like automatic incremental compilation and code snippet evaluation).

A programmers guide to JDT tooling can be found here.