Java and compiling when not using a IDE

Question

I understand in java that you are forced into a single file per class.

So if I have classes like:

/my_project/main.java
/my_project/classes/user.java
/my_project/classes/other.java

And my main.java references the user and other files, how would I compile this via the command line?

If I was to have external .jar's that I was referencing, and I placed them in a particular folder, how could I also include this in my compiling? (or is there a general place I can put them where they will be picked up automatically like how python does this)

Answer 1

to compile, you will need to specify each source file, from the my_project folder:

javac classes/user.java classes/other.java main.java

You can also specify jar files for your classpath with the -cp option:

javac -cp myjarfile.jar main.java

You may also need to fiddle with the -cp flag to make sure your classes folder is in the classpath.

Answer 2

First of all it's poor style to make Java classes starting with lowercase.

Only public classes need to be in their own file, but you can add as many package-private classes as you like to the same file (although this is seen as poor style).

That said, the easiest way would to compile your code would be:

javac /my_project/main.java /my_project/classes/user.java /my_project/classes/other.java

In any case, proper code layout should be that classes are in a directory structure matching their package.

EDIT : There is a fairly good explanation of conventions here http://www.particle.kth.se/~lindsey/JavaCourse/Book/Part1/Java/Chapter05/packagesImport.html

Answer 3

除了上述答案之外，您还可以使用Apache Ant之类的工具 ，以简化构建的配置（如果复杂）。

Answer 4

Look at the documentation for javac . You can pass multiple source files, or specify the source directory.