Java server won't run after reboot

[Bob Smith]

Oops, on the last example, set the classpath for a jar as follows:

export CLASSPATH=<pathtojar>/MyHelloWorld.jar
e.g.  Using /opt/myapp/lib as <pathtoyourclasslocation>
export CLASSPATH=/opt/myapp/lib/MyHelloWorld.jar

HTH,

-Bob


> Working with classpaths in Java isn't too hard, but there are some rules
> to follow.
>
> 1.  Simplest scenario:  Executing in the same directory, and there are no
> package definitions in your source code.  Example:  HelloWorld, no package
> definition.  Execute from that directory, no classpath definition needed.
> eg.
>
> Class HelloWorld { ... }
>
> 2.  Next simplest:  You compile without packages defined:
> using the same directory for source and compiled classes, or if you
> compiled classes to a different directory:
>
> export CLASSPATH=<pathtoyourclasslocation>
> example directory:  /opt/myapp/lib/
> then
> export CLASSPATH=/opt/myapp/lib/
> and call it:
> java HelloWorld
>
>
> 3.  Adding a package definition to your source code, and there is a
> definite source code hierachy.  Using the package example below:
>
> package project.testjava;
> Class HelloWorld { ... }
>
> Your directory structure should look like this:
> <pathtoyoursourcelocation>/project/testjava/HelloWorld.java
>
> Assuming that you compile your code in the same directory and deposit the
> class files there, then set your classpath as follows:
>
> export CLASSPATH=<pathtoyoursourcelocation>
> e.g. Using /opt/myapp/source/ as <pathtoyoursourcelocation>:
> ex.  export CLASSPATH=/opt/myapp/source/
>
> and call the application as follows:
>
> java project.testjava.HelloWorld
>
> --------------------------------------------
>
> If you compile to a different location, then your directory structure will
> look like this after a compilation:
>
> <pathtoyoursourcelocation>/project/testjava/HelloWorld.java
> <pathtoyourclasslocation>/project/testjava/HelloWorld.class
>
> Then set the classpath as follows:
> export CLASSPATH=<pathtoyourclasslocation>
> e.g.  Using /opt/myapp/lib as <pathtoyourclasslocation>
> export CLASSPATH=/opt/myapp/lib
>
> and call the application as follows:
>
> java project.testjava.HelloWorld
>
> 3.  You've compiled to a jarfile, e.g. MyHelloWorld.jar
> export CLASSPATH=<pathtojar>/MyHelloWorld.jar
> e.g.  Using /opt/myapp/lib as <pathtoyourclasslocation>
> export CLASSPATH=/opt/myapp/lib
>
> and call as follows:
> java project.testjava.HelloWorld
>
>
> -Bob
>
>> On Saturday 29 May 2004 05:44 pm, you wrote:
>>> That didn't work.  I still get the NoClassDefFoundError.  Any other
>>> ideas?
>>
>> You're right !! it doesn't work. I just try this myself, and whenever I
>> try to
>> execute from outside the directory where the java files is located, I
>> got
>> the
>> same error. I thought I've seen this and what I suggested was the
>> solution,
>> obviously not ! (Now it should be obvious that I am not a java developer
>> myself, I just play with it sometime)
>>
>> After some searching myself, I only have this solution:
>>
>> If for example, my java program is in
>> ~/project/testjava/helloworld.java,
>> I
>> can put in helloworld.java:
>>
>> package project.testjava;
>> <rest of the src code>
>>
>> then I need to go to ~, and compile it from there:
>> javac project/testjava/helloworld.java
>>
>> and running it from there would work tpp:
>> java project/testjava/helloworld
>>
>> The problems with the solution: First, I can't find a way so that I can
>> use
>> absolute path during compile and running (which is probably what you
>> want
>> in
>> your case, since you're going to put the command in rc.local). So what I
>> want
>> is something so that I can say:
>>
>> javac /home/<username>/project/testjava/helloworld.java
>> java /home/<username>/project/testjava/helloworld
>>
>> when I tried, the solution does not work. I can't also figure out what
>> to
>> put
>> in after the "package" keyword in the source code to make the absolute
>> path
>> work.
>>
>> Secondly, the source code is dependent on what directory you want to
>> compile
>> and run the java program from. Unless I am missing something, that is
>> just
>> plain stupid !! Source code of a program should never be dependent on
>> where
>> the program is running from.
>>
>> So that's it. I am kinda stuck right now too. I don't know if that would
>> help
>> you, but if you find the real solution, please let me know, cause right
>> now
>> it bugs the hell out of me too ! (BTW, I have a task of writing some
>> java
>> program in the near future, so this would be good to know).
>>
>> I know this is going OT, but if anyone else on the list know a solution,
>> please help.
>>
>> RDB
>>
>>
>>> On Sat, 2004-05-29 at 11:59, Reuben D. Budiardja wrote:
>>> > On Saturday 29 May 2004 12:16 pm, Michael Sullivan wrote:
>> <snip>I wrote a java server that I want to start every time
>>> > > my server PC restarts.  I created a /usr/local/classes directory
>>> and
>>> > > copied Server.class and the support classes it uses there.  Id cd'd
>>> to
>>> > > /usr/local/classes and issued a java Server from there and it works
>>> > > fine, but if I issue a java /usr/local/classes/Server from anywhere
>>> > > outside the /usr/local/classes directory it tells me
>>> > >
>>> > > Exception in thread "main" java.lang.NoClassDefFoundError:
>>> > > /usr/local/classes/Server
>> <snip>
>>> > Try the following:
>>> > set the environment variable CLASSPATH to /usr/local/classes so that
>>> Java
>>> > knows where to find your classes. Asumming you're using bash:
>>> > $> export CLASSPATH=$CLASSPATH:/usr/local/classes
>>> >
>>
>>
>> --
>> Reuben D. Budiardja
>> Department of Physics and Astronomy
>> The University of Tennessee, Knoxville, TN
>> ---------------------------------------------------------
>> "To be a nemesis, you have to actively try to destroy
>> something, don't you? Really, I'm not out to destroy
>> Microsoft. That will just be a completely unintentional
>> side effect."
>>                  - Linus Torvalds -
>>
>>
>> --
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