JavaRanch: Java Programming Style Guide
Style guide focusing primarily on formatting and comments, as well as advice on which coding constructs to avoid. http://www.javaranch.com/style.jsp
Java Programming Style Guidelines
A set of recommendations on various aspects of coding such as naming, file organization, and comments. http://geosoft.no/development/javastyle.html
Tips for maintainable Java code
A random collection of personal observations by Rolf Howarth. http://www.squarebox.co.uk/download/javatips.html
A Programming Style for Java
A large number of heuristic guidelines for writing well-structured and maintainable Java programs. (October 26, 1999) http://www.webcom.com/~haahr/essays/java-style/
Java Coding Standards
Collection of links Ray Ontko. http://www.ontko.com/java/java_coding_standards.html
The Infospheres Java Coding Standard
Discusses structure, documentation, naming conventions. Also discusses useful related tools. http://www.infospheres.caltech.edu/resources/code_standards/java_standard.html
Coding Standards for Java
Comprehensive coding and style guidelines from AmbySoft Inc. http://www.ambysoft.com/essays/javaCodingStandards.html
Draft Java Coding Standard
Guidelines for structure, documentation and naming. http://gee.cs.oswego.edu/dl/html/javaCodingStd.html
How To Write Unmaintainable Code
A humorous approach emphasizing the need for coding standards - Java centric discussion. http://www.mindprod.com/jgloss/unmain.html