Compiling custom imports

[Animesh Gupta]

Hi All,
I was doing fine with my code until I scribbled an import for my custom made class.

The scenario is, I have a class Selector. it is inside the package

 com.example.web.Selector.java 

.
Now, I am trying to import another class called Expert.java which is in the package

 com.example.model.Expert.java 

.

 com.example.web.Selector.java 

is trying to use the class

 com.example.model.Expert.java 

.
The import I wrote --

 "com.example.model.*;" 

inside the Selector.java class.

No when I am trying to compile the class Selector.java from the command prompt and I am getting error saying

 .\com\example\web\Selector.java:6: package com.example.model does not exist
import com.example.model.*;
^
.\com\example\web\Selector.java:14: cannot find symbol
symbol  : class Expert
location: class com.example.web.Selector
                Expert brExp = new Expert();
                ^
.\com\example\web\Selector.java:14: cannot find symbol
symbol  : class Expert
location: class com.example.web.Selector
                Expert brExp = new Expert(); 

Hey guys please help for how to compile my file Selector.java. It is important as I have to finish this by tonight.

Any kind of help will be really appreciated.

Thanks and Regards
Animesh

[Martin Vanyavchich]

Well ... package com.example.model does not exist. Either it's not in your CLASSPATH, or its directory structure is wrong, there might be no package declaration in Expert.java class, maybe your Expert class wasn,t compiled.

Could you paste your actual code and directory structure?

[Animesh Gupta]

Hi Martin,
Thanks for the prompt reply.

1.) The package -- com.example.model does exists.

2.) The Expert.java class does have the package declaration as

 package com.example.model; 

3.) The directory structure is right. Both the packages, web and model fall under the package com.example.

4.) The Expert.java class is compiled.

5.) The actual code is too long to paste here. I am pasting the imports for you in both classes

For Selector.java

package com.example.web;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import com.example.model.*;
import java.util.*;

For Expert.java

package com.example.model;

import java.util.*;

6.) Why do I need to add Exper.java in my CLASSPATH ?

7.) When I tried by adding the class Expert.java in my CLASSPATH, still I got the same error

.\com\example\web\Selector.java:6: package com.example.model does not exist  
import com.example.model.*;  
^  
.\com\example\web\Selector.java:14: cannot find symbol  
symbol  : class Expert  
location: class com.example.web.Selector  
                Expert brExp = new Expert();  
                ^  
.\com\example\web\Selector.java:14: cannot find symbol  
symbol  : class Expert  
location: class com.example.web.Selector  
                Expert brExp = new Expert();

Really going nuts with problem. No obvious reason for which it is not working.

Thanks and Regards
Animesh

[Martin Vanyavchich]

Hey Animesh,

are you using command line compiler or some kind of IDE, like NetBeans or Eclipse?

If you're using command line try adding classpath option. Lets say you have your code in C:\com\example\model and C:\com\example\web

javac -classpath C:\com\example\model; C:\com\example\web\Selector.java

Try playing around with -classpath option, you can use -cp if you don't like excessive typing

[Animesh Gupta]

Hi,
No luck with the above suggest as well.

I would like to simplify my prob. I have 2 source files. One is compiled and I am using this compiled file as an import in my other source file.

Both the source files are in different packages.

When I go ahead and compile my source file which using the other one as an import then I get the error stating that the package which I have used as the import does not exists.

I have tried to compile setting that package in classpath as well. But, no luck.
I have used various compiling options with javac, like, -classpath, -cp, -sourcepath, but still no luck.

The directory structure I am having is like this

C:\...\com\example\web\Selector.java 

and

C:\...\com\example\model\Expert.java 

I am trying to import

 com.example.model.Expert.java 

into

com.example.web.Selector.java 

Help needed regarding how to compile successfully Selector.java

Thanks and Regards
Animesh

[Martin Vanyavchich]

Might be that your classes are not public?

I tryied to reproduce your problem.. My structure is:

C:-
   |-Martin
       |-SCJP
           |-com
               |-example
                    |-model
                    |   |-Expert.java
                    |
                    |-web
                        |-Selector.java

I went to C:\Martin\SCJP\com\example\web and execute:

javac -cp C:\Martin\SCJP Selector.java

This compiles.

Did this help you?

[Animesh Gupta]

Ok Martin,
first of all I would like to say thanks for all your effort for getting around my problem. Thanks

Let me tell you little more ... My directory structure is like

 C:\MyProjects\BeerV1\src\com\example\web\Selector.java 

and

 C:\MyProjects\BeerV1\src\com\example\model\Expert.java 

I have to compile and deploy these files at the following locations

 C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes\com\example\web\Selector.class 

and

 C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes\com\example\model\Expert.java 

The command I am using at command prompt is like this

 C:\MyProjects\BeerV1\src>javac -classpath C:\Java\apache-tomcat-7.0.0-src\output\build\lib\servlet-api.jar -d C:\Java\apache-tomcat-7.0.0-src\ou
tput\build\webapps\BeerV1\WEB-INF\classes -sourcepath .\com\example\web .\com\example\web\Selector.java 

Simplifying the above command, I am placed at

 C:\MyProjects\BeerV1\src> 

that I am at the base of my package structure, i.e., at the base of "com" directory.
Now, I have to include the servlet-api.jar in the classpath

 javac -classpath C:\Java\apache-tomcat-7.0.0-src\output\build\lib\servlet-api.jar 

deploying at

 -d C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes 

sourcepath is set at

 sourcepath .\com\example\web 

the source file is at

 .\com\example\web\Selector.java 

This is the whole situation.

Might be that your classes are not public?

Both my classes Expert and Selector are declared coderanch.

Thanks and Regards
Animesh.

[Martin Vanyavchich]

I can olny hope I've put this thing together correctly

Given that you are placed in: C:\MyProjects\BeerV1\src>

javac -classpath "C:\Java\apache-tomcat-7.0.0-src\output\build\lib\servlet-api.jar";"C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes\" -d "C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes"  .\com\example\web\Selector.java

Is this an example from a Sierra/Bates book? Looks familiar. Please quote your sources.

[Rene Larsen]

How do you compile your classes??

If you do it the right way you only need to compile Selector.java - and then Expert.java will be compiled automatically.

If you navigate to "C:\MyProjects\BeerV1\src" and from there compile your class

compile:

C:\MyProjects\BeerV1\src>javac -classpath C:\Java\apache-tomcat-7.0.0-src\output\build\lib\servlet-api.jar -d C:\Java\apache-tomcat-7.0.0-src\output\build\webapps\BeerV1\WEB-INF\classes com\example\web\Selector.java

[Animesh Gupta]

Hey Martin/Rene,
Thanks for the replies.

Martin man you cracked it. I was like laughing and thinking about how did it missed that second classpath setting.

And yes that is a Sierra/Bates book's example. Are you a programmer detective ?
Actually I am new to servlet programming. So, I was trying out the example given in the book.

Thanks a lot you saved me lots of time.

Hey Rene, Thanks for your effort as well. I tried out your way of putting up the command line. But, it again threw the same error saying

 .\com\example\web\Selector.java:6: package com.example.model does not exist
import com.example.model.*;
^
.\com\example\web\Selector.java:14: cannot find symbol
symbol  : class Expert
location: class com.example.web.Selector
                Expert brExp = new Expert();
                ^
.\com\example\web\Selector.java:14: cannot find symbol
symbol  : class Expert
location: class com.example.web.Selector
                Expert brExp = new Expert();
                                       ^ 

But thanks anyways. I appreciate your effort of going through the previous posts and putting up a suggestion.

Thanks and Regards
Animesh

[Rene Larsen]

Try to put a dot (.) in the classpath - and then remove the .\ from your java class

it should look like this

javac -classpath .;C:\Java\apache-tomcat-7.0.0-src\out... -d ...webapps\BeerV1\WEB-INF\classes com\example\web\Selector.java

[Animesh Gupta]

Hey Rene,
Kudos ... you gave me an alternate solution as well.

Really cool. It worked fine all the way.

Thanks and Regards
Animesh