javac "an incomplete discussion"

[Chandra Bhatt]

I lost the thread where this discussion was going on, but meanwhile left
without any final conclusion.

javac finds the needed source file and complies them as well with the main
source file.

I disagreed with that.

"javac -cp only finds class files. If the needed class file does not exist,
it gives compiler error."

What I know:
"Suppose Source A.java is using B's (public class) instance and methods so when you complile A.java, B.class must be present in order to compile A.java."

Is that right? Yes(OK)/No(Why?)

Thanks,
cmbhatt

[Barry Gaunt]

Follow through this:

barry@ours:~$ mkdir top
barry@ours:~$ cd top
barry@ours:~/top$ mkdir one two
barry@ours:~/top$ ls
one  two
barry@ours:~/top$ cd one
barry@ours:~/top/one$ cat > A.java
package one;
import two.B;
class A {
    public static void main(String... args) {
        new B();
    }
}
barry@ours:~/top/one$ cd ../two
barry@ours:~/top/two$ cat > B.java
package two;
public class B {
    public B(){System.out.println("Hi from B");}
}
 

barry@ours:~/top/two$ cd ..
barry@ours:~/top$ export CLASSPATH=`pwd`
barry@ours:~/top$ echo $CLASSPATH
/home/barry/top
barry@ours:~/top$ cd one
barry@ours:~/top/one$ ls
A.java
barry@ours:~/top/one$ javac A.java
barry@ours:~/top/one$ ls ../two
B.class  B.java
barry@ours:~/top/one$
 

Where did B.class come from?

[Chandra Bhatt]

Sorry Barry but I couldn't completely understand the code
provided by you!





Please elaborate!

Waiting...
cmbhatt

[Ulf Dittmer]

Which step is giving you difficulties? Were you able to do them all yourself?

[Chandra Bhatt]

Alright Barry! I got exactly what you did there!

My question is if B.class does not exist in the "two" directory,
and we try to compile A.java that is in the "one" directory,
would it also compile B.java that is in the "two" directory.
I know it is senseless question.

We must compile B.java before we can compile A.java, because
javac will search for B.class and not B.java.

We can do it in one line two like:

top>javac one/A.java two/B.java

italics is my doubt and bold is what it should be!

Guide me!!

Thanks,
cmbhatt

[Barry Gaunt]

would it also compile B.java that is in the "two" directory?

Well, that's what it did! I certainly did not compile it.

[Chandra Bhatt]

Great Barry,

I did the same, and it worked. B.class automatically created in
"two" directory.

But if we give classpath (-cp) with javac, then what happens.


Thanks,
cmbhatt