Development

Java tutorials

Compiling classes
Dates
Files
Lists and Maps
Timers
Enum
Threads
Property files
Socket client and Socket server
Regular Expressions
Generics
Comparing objects and sorting arrays
Callback routines
Applets
Shutdown hook
Download file via HTTP
Encryption and hashing

Java APIs and tools

Apache Ant
Apache Derby
OSGI
log4j
JSON
Maven

Java on the network

Java Web Start (JNLP)
Apache Tomcat server
JBOSS server
Java Servlets
JSP - Java Server Pages
JSF - Java Server Faces
JPA - Java Persistence API
JPA Relations
SOAP web services with JAX-WS
SOAP web services with Axis2
RESTful web services
Using Apache Hadoop with Java

Web technologies

HTML - basics of web pages
CSS - web page look and feel
PHP - add brains to web page
JavaScript - user-side code
DHTML - user interactions
XML - structured data
SOAP with JAX-WS
REST web services

Database

MySql
Apache Derby
InfluxDB
Apache Hadoop HDFS

Eclipse

Remote debugger
Database perspective
Set up JSF environment

Miscellaneous

Development environment
FTP Command Line
Handy linux commands
Things to do after CentOS 7 installation
Git
Python
Shell
CGI & Perl