These are various small pieces of code that I created over the years for some purpose or other, mostly in Java. Some of them may be helpful to others, so I've put them here for wider access.

  • ExprJava is a Java class that evaluates a mathematical expression by using a recursive-descent parser. It also handles variable substitution, and is useful for evaluating user-entered expressions.

  • AntTask shows how to extend Ant with custom tasks

  • WhoisLookup contains an implementation of a WHOIS lookup, based on the Apache Commons Net library (which has some limitations)

  • WebSockets shows how to use web sockets and server-sent events between a web page and a Java web app

  • SimpleMandel is a Java applet for displaying Mandelbrot sets of different exponents

Creating and altering PDF files

If any of my code snippets and examples has been helpful to you or your company, and you feel like expressing your gratitude beyond saying Thank you, please note that I have an Amazon Wish List containing several inexpensive items, or you can contribute directly via PayPal.

  • PdfBox is an example of how to create a PDF file with the Apache PDFBox library, and how to use a few of its capabilities

  • PdfboxAnnotation shows how to alter the appearance of text in a PDF (highlighting, underlining and striking out) using the PDFBox library

  • PdfboxTable shows how to add tables to a PDF using the PDFBox and Boxable libraries

  • PdfboxReplace shows how to search and replace text in a PDF in some circumstances using the PDFBox library

Some applets from way back when, written by other people, resurrected here so they don't get lost.

  • HexCalc is a simple calculator with binary, octal, decimal and hexdecimal modes

  • Martin Minow's SunSphere applet shows a picture of the rotating earth, complete with sunlight and night shadow