Compilation of java files using javac -d option

[Jignesh Gohel]

Hello,
If i have the following structure :

MyProject
src
    com
       samples
    java
 pack1
pack2
pack3
classes

In pack2 directories there are some classes which depends on some classes in pack3 directories and vice-versa.

Now if i want to compile the src files using the following command pattern:
javac -d classes src

how to do it..
i have tried but it gives compilation errors.

And can somebody please let me know how Eclipse does it when it automatically compiles the code we are writing???


Thanks.

[Campbell Ritchie]

It is awkward; you have to start compiling the file which has no dependencies on any other files in your package structure. It is the one farthest from the main method, which can be difficult to guess.

The class with the main method in will be compiled last. Slightly easier to guess which one.

Don't know how the IDEs do it.

[Garrett Rowe]

Its not that bad, if a dependent class is on the source path the javac will find it and compile it. That said, I use Windows mostly and I usually just write a script called compile and call that from the command line, I keep all my class names listed in separate text file:

compile.bat

echo off
rmdir /s /q classes
mkdir classes
javac -cp classes;. -d classes @resources\sourceclasses.txt
echo on

\resources\sourceclasses.txt

src\packageone\Foo.java
src\packageone\subpackage\Bar.java
src\tests\FooTest.java
src\tests\BarTest.java

[ April 19, 2007: Message edited by: Garrett Rowe ]

[Jignesh Gohel]

Thanks Garrett,

Its not that bad, if a dependent class is on the source path the javac will find it and compile it.

If you have any knowledge regarding how come this works please let me know i am very much curious to know about this.

Thanks

[kiran kumar kondru]

You can otherwise set the CLASSPATH to the correct directory i.e.

CLASSPATH=src;

probably your files in source are in good package structure.

How this works? Here it is

when you set the classpath to src, the javac or java uses them to find other classes. For this situation your file in pack2 will have the package statement as

package com.samples.java.pack2;

when this statement is encountered it checks whether a folder named "com" exists or not. for this it checks all the paths set in the classpath variable. since our classpath is set, it find com and it finds samples etc.