Want to be a Java developer?

Java is one of the top 3 programming languages in the world. It can be used to develop both web applications and desktop applications and more importantly it is cross platform--write once, run everywhere. Also, it's easy to pick up. If you want to be a Java developer, please get to ask yourself whether you know below listed topics.

This list is summarized by Vivek Vermani, a Senior Java Developer:

For a Core Java Developer , Ffollowing topics should be good.

• OOPs Concepts
• Abstract Classes and Interfaces
• Constructors and initialization order
• File IO and Serialization
• Collections - List , Map , Set
• Access Specifiers
• Exceptions - Checked , Unchecked
• Generics
• Java Keywords - Static , Final , volatile, synchronized , transient, this super etc.
• JVM and Memory Management
• Multithreading and Synchronization
• Design Patterns
• Reflections
• Lambda Expressions

Here is a list of 200+ questions on Core Java - Java - Interview Questions and Answers - Quick Reference - One Liners.

If you want to focus on Network / Distributed Application, Following topics can be asked

• Communication Protocols like IP, HTTP, TCP, FTP,UDP (Reading some RFCs is necessary)
• Synchronous vs Asynchronus Communication
• Sockets
• Technologies like RMI, RCP
• Message Queues
• Interface APIs - JMS, JDBC , ORM , Hibernate

If you want to work Java based web application then following topics should be learned -

• JSP / Servlets
• Web Frameworks like Struts / Spring
• Service Oriented Architecture / Web Services - SOAP / Rest
• Web Technologies like HTML, CSS, Javascript and JQuery
• Markup Languages like XML and JSON.
• Application and Web Servers (Tomcat)
• Caching
• Web application servers (WebLogic, WebSphere)
• Some cloud service (AWS, SoftLayer, BlueMix)
• Some libraries (Java mail, log4j, Jackson JSON)

If you want to work on Java UI, then following topics can be learned -

• Applets
• Frameworks like Swing, SWT, AWT
• Advanced Framewroks like JavaFX, JMF

Every Java Developer is expected to have Database Knowledge

• SQL Queries - Inner Outer Joins, Group By , Having
• Stored Procedures
• Triggers
• Cursors
• Database drivers (JDBC)
• JavaBeans

Moreover questions around Tools, Methodologies, Processes can be asked -

• Development Tools - Eclipse / RAD / IntelliJ IDEA
• Design Tools and Diagrams
• Configuration Management Tools like SVN, Clearcase etc
• Defect Management
• Build Tools like Maven, Ant etc
• Testing - Unit Testing, JUnit , Black box , White Box
• Development Methodologies - Agile / Waterfall / Iterative
• Requirement Analysis
• Release Management
• Reverse engineering -- JadClipse(A Java decompiler)
• OpenJDK source code --(Mercurial on Eclipse)

Here are few links that might help.

• The Java Tutorials
• Java revisited
• JavaWorld
• Java2s -- Many Java code snippets
• Java - Interview Questions and Answers - Quick Reference - One Liners
• Java web tutorials
• Java Concurency/Multithreading Tutorials
• Introduction to Java programming - Tutorial
• 200+ Java / J2EE Interview Questions and Answers
• Struts Framework - Interview Questions and Answers
• Spring Interview Questions FAQs Interview Questions Spring Tutorial JSF Interview Questions Hibernate Interview Questions
• WAS / WSAD / RAD - Interview Questions and Answers
• JavaScript interview questions and answers
• Interview Questions and Answers on Markup Languages - XML , JSON