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

  • 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