Real Java learning from getting started to mastering

A, tool JDK (Java Development Kit)
The JDK is the core of the entire Java system, including the Java Runtime Environment (Java Runtime envirnment), a stack of Java tools and a Java-based class library (Rt.jar). No matter what Java application Server is in essence a version of the JDK is built in. So mastering the JDK is the first step in learning java. The most mainstream JDK is the JDK that Sun releases, and many companies and organizations, in addition to Sun, have developed their own JDK, such as the Jrocket of IBM's Jdk,bea company, the JDK developed by the GNU organization, and so on. IBM's JDK contains JVM (Java Virtual Machine) that is much more efficient than the JVM contained in the Sun JDK. The Jrocket, which runs on the x86 platform, is also much better at the server than the Sun JDK. But anyway, we need to get the sun JDK first.
1, the JDK download and install
The JDK, also known as J2SE (Java2 SDK Standard Edition), can be downloaded from the Sun's Java Web site, http://java.sun.com/j2se/downloads.html, The current version of the JDK is j2sdk1.4.2, and it is recommended that you download this version of the JDK, download the page here: http://java.sun.com/j2se/1.4.2/download.html. The downloaded JDK is an executable installer that installs a set of JRE (for browsers to use) under the C:Program Filesjava directory after the default installation, and installs a set of JDK (also includes a JRE) under c:j2sdk1.4.2. Then we need to add the Java path c:j2sdk1.4.2in to the front of the environment variable path. So the JDK is installed.
2, the JDK command tool
The most important command-line tool for JDK:
Java: Start JVM execution class
Javac:java compiler
Jar:java Packaging Tools
Javadoc:java Document Builder
These command lines must be very, very familiar and proficient for each parameter. For the learning of these commands, the JDK documentation has detailed documentation.
Second, JDK documentation
Documentation also has a download link on the JDK download page and recommends downloading documentation at the same time. Documentation is the most important programming manual, covering all aspects of the entire Java description of the content. It can be said that learning Java programming, most of the time is spent looking at the documentation above. I was carrying, write Java code, at any time to view, a moment of the hand.
Third, Application server (app server)
App Server is a platform for running Java Enterprise Components, which forms the main operating environment of the application software. The current mainstream app server is Bea's WebLogic server and IBM's WebSphere and free JBoss, choose one to learn from, and personally recommend WebLogic, because its architecture is cleaner, Development and deployment is more convenient, is the Java enterprise Software developers preferred development platform. The following is a brief introduction to several commonly used app servers: