Learn Android: HelloWorld directly from the JDK

This article knows a little bit about the Java compilation mechanism, and tries the pure JDK to HelloWorld

See the JDK tool in the bin directory of the JDK installation location

There are a lot of JDK tools, of course, and the bin at the same level of the directory there are JRE, lib,db and other tools.

A simple understanding of the next Java mechanism,

Use Javac (compile) to compile the source code, which is the suffix. java file, output the class file as a byte code. This is not a direct-to-run file,

It is an interpreter code that needs to be interpreted and run under the Java Virtual Machine (JVM) in the JRE. This is similar to C #, first compiled into an intermediate language, and then to

The. NET environment goes on to explain the run. With such an intermediate process, it is very good to achieve platform-independent. And that's really the advantage of Java.

So in the history of computer development language, no language has been supported by so many vendors as Java, there are so many development tools.

By the way, the relationship between these things:

Under the moving small hand, the name of the class to be consistent with the file name, the name can only be Hello.java

Make the environment variable so that the tools in front of the Jdk/bin directory are easy to call, my Ubuntu is in ~/.profile Edit Export path= jdk. /bin: $PATH

In Source ~/.profile

Learn Android: HelloWorld directly from the JDK