[java] how to convert .java file to a .class file

Can anyone tell me how I can convert a .java file into .class file with an executable bytecode?

A .java file is the code file. A .class file is the compiled file.

It's not exactly "conversion" - it's compilation. Suppose your file was called "herb.java", you would write (in the command prompt):

 javac herb.java

It will create a herb.class file in the current folder.

It is "executable" only if it contains a static void main(String[]) method inside it. If it does, you can execute it by running (again, command prompt:)

 java herb

From the command line, run

javac ClassName.java

Use the javac program that comes with the JDK (visit java.sun.com if you don't have it). The installer does not automatically add javac to your system path, so you'll need to add the bin directory of the installed path to your system path before you can use it easily.

After compiling it you can jar it.

java -jar AppName.jar

http://windowstipoftheday.blogspot.com/2005/10/setting-jar-file-association.html

As the others stated : it's by compiling. You can use the javac command, but I'f you're new at java, I suggest you use a software for compiling your code (and IDE) such as Eclipse and it will do the job for you.

To get a .class file you have to compile the .java file.

The command for this is javac. The manual for this is found here (Windows)

In short:

javac File.java

I would suggest you read the appropriate sections in The Java Tutorial from Sun:

http://java.sun.com/docs/books/tutorial/getStarted/cupojava/win32.html