Author: Chip Killmar

It’s more difficult to download Sun’s JDK 1.5 now (version 1.5.0_22 to be precise as I write this) that the company has officially announced its end-of-life.  Downloading it by following the normal path on Sun’s website will land you at a registration form explaining that “Sun offers Java SE for Business, a service offering that provides Read More …

XPath is usually the perfect language, providing a simple and elegant way to compute values from the content of an XML document. For example, say that you want to count the number of elements. The XPath 1.0 query for this is about as concise as it gets: 1 XPathFactory xPathFactory = XPathFactory.newInstance(); 2 XPath xPath Read More …

If you’re like me it can be useful to convert a DOM in Java into a formatted XML string. Pretty-printing a DOM Element can augment the information gleaned from your debugger when tracking down a  bug, for example. I’ll show you three ways to pretty-print XML from a Java DOM below.  All of them format Read More …

Before the introduction of Generics in Java 5 it’s commonly known that in a class you can’t have two methods with the same signature that differ by return type alone.  More formally, the Java Language Specification §8.4.2 says that “it is a compile time error to declare two methods with override-equivalent signatures in a class”.  Take Read More …

Apache POI is a full-featured Java library for reading several different Microsoft file formats, including Excel. (Note: this post only covers POI version 3.0.2-FINAL released in February 2008). POI supports evaluating cells with formulas containing Excel functions. For example, consider the code below for reading a java.util.Date from a simple spreadsheet with the formula “=NOW()” Read More …

Have you noticed that your smallest time deltas using System.currentTimeMillis() are usually 15 or 16 milliseconds on Windows?