Compiling and running two source files

[Claude Cundiff]

Hello everyone!

I'm having some problems understanding how to use packages. I'd really appreciate any help you could provide.

I have two source files (Meaty.java, Classy.java) in directories like this:

C:\
---Java_Programs
-------com
----------test
--------------Meaty.java
--------------Classy.java

where Meaty calls Classy in its constructor
Here are the source files:

   
//Classy.java-------------------------------
package com.test; 
 
public class Classy { 
 
public Classy() { 
System.out.println("You've got class!"); 
} 
 
} 
 
//Meaty.java -------------------------------
package com.test; 
 
import com.test.Classy;
   
public class Meaty { 
 
public Meaty(){ 
System.out.println("Meaty"); 
Classy C = new Classy();
} 

public static void main(String[] args){
new Meaty();  


}
 
} 
 

Here is my failed attempt to compile these via command prompt:

C:\Windows\system32>cd C:\Java_Programs
C:\Java_Programs>set CLASSPATH=C:\Java_Programs
C:\Java_Programs>javac -CLASSPATH com\test\*.java

This doesn't work at all.

I've done searches on how to do this. I've looked in all my java books but I'm just not getting this.

Thanks

[marc weber]

Originally posted by Claude Cundiff:
...Here is my failed attempt to compile these via command prompt:

C:\Windows\system32>cd C:\Java_Programs
C:\Java_Programs>set CLASSPATH=C:\Java_Programs
C:\Java_Programs>javac -CLASSPATH com\test\*.java
...

It looks like you're setting the classpath correctly (C:\Java_Programs), but then reseting it to nothing in the next line. Try invoking javac without the -CLASSPATH flag.

[Claude Cundiff]

Tried the following:

C:\Java_Programs>javac com\test\*.java

'javac' is not recognized as an internal...

also, I checked the classpath with set CLASSPATH. It doesn't appear to be reset...

[marc weber]

Originally posted by Claude Cundiff:
...'javac' is not recognized as an internal...

That suggests that your PATH is not updated. See step 4 of the installation instructions.

[Claude Cundiff]

Thanks marc!!

I don't know what I'd do if it were not for your site!

If any newbies are reading this by some chance, when you run your compiled class, observe that the "\" becomes "/" - at least on Vista.

[marc weber]

Also note that if no classpath is specified, Java's default is to check the current directory. So unless you have an environment variable set for classpath (and it does not include a dot for the current directory), you shouldn't need to set classpath at all for this example.

[Claude Cundiff]

marc,

Yeah, when I looked in my environment variables, I had
c:\Programs\Java\jdk1.6.0\bin

I forgot the _05 part.

So from what you are saying, if the path was just set to "." (parenthesis not included) then the whole classpath thing is not needed. So I need to do two things:
1.) set CLASSPATH = "" (set it to nothing) and
2.) change path = .; in the environment variable (or is it .*

Correct?

Again, thanks for your help.

[marc weber]

I think that's a little confused. You should not set your CLASSPATH to nothing, and you should not set PATH to include "." (the current directory).

PATH tells your system where to find executables like javac and java. With this set, you can type "javac" at the command line, and your system will make sense of it. In addition to whatever is already there, your PATH should include...

c:\Programs\Java\jdk1.6.0_05\bin

...because that's where the Java executables are.

CLASSPATH tells Java where to find user-specified Java classes. The default is to use the current directory (.), so normally you don't need to do anything. If you set CLASSPATH to nothing, then you will not get the default behavior.

So (after correcting your CLASS variable) you should be able to just change the directory and compile...

C:\Windows\system32>cd C:\Java_Programs
C:\Java_Programs>javac com\test\*.java

[Claude Cundiff]

Thanks marc, this is starting to make sense.