What You Need to Start: Java Programming for Androids

Before you can write Java programs for Android devices, you need some software tools. Some tools are necessary; some are optional. Here’s a list of the tools you need:

• A Java virtual machineCool people refer to this item as the JVM or simply as Java.
• The Java code librariesThese code libraries are known affectionately as the Java Runtime Environment (JRE) or simply as Java.

PCRE regex

The syntax and semantics of the regular expressions supported by PCRE are described below. Regular expressions are also described in the Perl documentation and in a number of other books, some of which have copious examples. Jeffrey Friedl’s “Mastering Regular Expressions”, published by O’Reilly (ISBN 1-56592-257-3), covers them in great detail. The description here is intended as reference documentation.

A regular expression is a pattern that is matched against a subject string from left to right. Most characters stand for themselves in a pattern, and match the corresponding characters in the subject. As a trivial example, the pattern “The quick brown fox” matches a portion of a subject string that is identical to itself.