Wikipedia is recommended as an entry into any/the following topics;
Requirement elicitation, object oriented analysis (OOA), use cases, scenarios,
object oriented design (OOAD),domain driven design, UML, design patterns, dependency injection, or whatever...
RAD Template
Other RAD Template
Writing a good SD
Agile documentation
Maven tutorial
Git tutorials for beginners
JUnit tutorials
Findbugs (general code quality)
STAN (Structure analysis)
JDepend (dependency analysis)
Google : Window builder
NetBeans GUI Builder
SwiXML (GUI builder)
Beryl XML (GUI Builder)