A Programming Style for Java
   A large number of heuristic guidelines for writing well-structured and maintainable Java programs.
   http://www.webcom.com/~haahr/essays/java-style/

Code Conventions for the Java Programming Language
   Coding Guidelines from Sun Microsystems.
   http://java.sun.com/docs/codeconv/

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

How to Write Doc Comments for the Javadoc tool
   "Official" JavaDoc style guidelines from Sun Microsystems.
   http://java.sun.com/j2se/javadoc/writingdoccomments/index.html

Java Coding Standards
   Collection of links Ray Ontko.
   http://www.ontko.com/java/java_coding_standards.html

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

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

Tips for maintainable Java code
   A random collection of personal observations by Rolf Howarth.
   http://www.squarebox.co.uk/download/javatips.html