Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.java.programmer > #10477 > unrolled thread

Linking Jars

Back to article view | Back to comp.lang.java.programmer

Contents

  Linking Jars Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 19:53 -0800
    Re: Linking Jars Roedy Green <see_website@mindprod.com.invalid> - 2011-12-03 20:00 -0800
      Re: Linking Jars Robert Klemme <shortcutter@googlemail.com> - 2011-12-04 11:20 +0100
        Re: Linking Jars Lew <lewbloch@gmail.com> - 2011-12-04 10:37 -0800
          Re: Linking Jars Robert Klemme <shortcutter@googlemail.com> - 2011-12-04 23:24 +0100
          Re: Linking Jars Roedy Green <see_website@mindprod.com.invalid> - 2011-12-05 04:20 -0800
            Re: Linking Jars ilAn <idonot@wantspam.net> - 2011-12-05 21:49 +0200
              Re: Linking Jars Tom Anderson <twic@urchin.earth.li> - 2011-12-06 22:11 +0000
            Re: Linking Jars Arne Vajhøj <arne@vajhoej.dk> - 2011-12-05 22:11 -0500
            OT: Was Re: Linking Jars RedGrittyBrick <RedGrittyBrick@spamweary.invalid> - 2011-12-07 15:11 +0000
        Re: Linking Jars Tom Anderson <twic@urchin.earth.li> - 2011-12-04 20:25 +0000
          Re: Linking Jars markspace <-@.> - 2011-12-04 13:43 -0800
            Re: Linking Jars Tom Anderson <twic@urchin.earth.li> - 2011-12-06 22:06 +0000
    Re: Linking Jars Ronny Schütz <usenet.r96@gishpuppy.com> - 2011-12-04 23:18 +0100

#10477 — Linking Jars

Lets say you have two jars and you want to treat them logically as
one.   This might happen if your program needs some third party
library.  What are your options?

1. mention the second jar in the -classpath

2. install the jar in the ext directory

3. extract the members you need from the library and add them all to
the main jar.  

4. extract the members you need from the library and add them to the
main jar. (How do you find out which you need, especially for a
plug-in that dynamically loads classes.)

5. Use JNLP where you can specify secondary jars.

Are there any other options?

Is there anything comparably WORA and free to JNLP for installing
ordinary apps so that they look like C apps to Windows users.
-- 
Roedy Green Canadian Mind Products
http://mindprod.com
For me, the appeal of computer programming is that
even though I am quite a klutz,
I can still produce something, in a sense
perfect, because the computer gives me as many
chances as I please to get it right.
 

[toc] | [next] | [standalone]

#10478

On Sat, 03 Dec 2011 19:53:37 -0800, Roedy Green
<see_website@mindprod.com.invalid> wrote, quoted or indirectly quoted
someone who said :

>Are there any other options?

for example, is there something you can put in the main jar that
points to the second?

I left out changing the global classpath. They are too fragile.
-- 
Roedy Green Canadian Mind Products
http://mindprod.com
For me, the appeal of computer programming is that
even though I am quite a klutz,
I can still produce something, in a sense
perfect, because the computer gives me as many
chances as I please to get it right.
 

[toc] | [prev] | [next] | [standalone]

#10482

On 04.12.2011 05:00, Roedy Green wrote:
> On Sat, 03 Dec 2011 19:53:37 -0800, Roedy Green
> <see_website@mindprod.com.invalid>  wrote, quoted or indirectly quoted
> someone who said :
>
>> Are there any other options?
>
> for example, is there something you can put in the main jar that
> points to the second?

Exactly.  And it would be my first choice.

http://docs.oracle.com/javase/1.4.2/docs/guide/jar/jar.html#Main%20Attributes

Cheers

	robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

[toc] | [prev] | [next] | [standalone]

#10491

Robert Klemme wrote:
> Roedy Green wrote:
>> Roedy Green wrote, quoted or indirectly quoted someone who said :
>>> Are there any other options?
>>
>> for example, is there something you can put in the main jar that
>> points to the second?
> 
> Exactly.  And it would be my first choice.
> 
> http://docs.oracle.com/javase/1.4.2/docs/guide/jar/jar.html#Main%20Attributes

I assume your point in using a 1.4 version of the docs is to indicate how long this information has been documented in the standard reference.

Amazing what the documentation can reveal if one were *ACTUALLY TO READ IT*.

I do think one should link to current versions of the docs most of the time, though.  For example, 
<http://docs.oracle.com/javase/tutorial/deployment/jar/downman.html>

No matter how long you've been programming in Java, the tutorials are valuable and for such elementary questions make a great starting point.

For the "main attributes" of the JAR manifest that you linked, that current version seems to be
http://docs.oracle.com/javase/6/docs/technotes/guides/jar/jar.html#Main%20Attributes

I encourage everyone to read the documentation.

Repeatedly.  Reviewing the basics is necessary.

-- 
Lew
You don't have to be a "language lawyer" (whatever the F that is) to read the JLS.

[toc] | [prev] | [next] | [standalone]

#10501

On 12/04/2011 07:37 PM, Lew wrote:
> Robert Klemme wrote:
>> Roedy Green wrote:
>>> Roedy Green wrote, quoted or indirectly quoted someone who said
>>> :
>>>> Are there any other options?
>>>
>>> for example, is there something you can put in the main jar that
>>> points to the second?
>>
>> Exactly.  And it would be my first choice.
>>
>> http://docs.oracle.com/javase/1.4.2/docs/guide/jar/jar.html#Main%20Attributes
>
> I assume your point in using a 1.4 version of the docs is to indicate
> how long this information has been documented in the standard
> reference.

Actually it was a tad different: I just grabbed the first ref my 
favorite search engine turned up - convinced that the classpath 
attribute didn't change. :-)

> Amazing what the documentation can reveal if one were *ACTUALLY TO
> READ IT*.

:-)

> I do think one should link to current versions of the docs most of
> the time, though.  For example,
> <http://docs.oracle.com/javase/tutorial/deployment/jar/downman.html>

Right.

> No matter how long you've been programming in Java, the tutorials are
> valuable and for such elementary questions make a great starting
> point.
>
> For the "main attributes" of the JAR manifest that you linked, that
> current version seems to be
> http://docs.oracle.com/javase/6/docs/technotes/guides/jar/jar.html#Main%20Attributes

Also a good point of reference.

>  I encourage everyone to read the documentation.
>
> Repeatedly.  Reviewing the basics is necessary.

+1

Today everybody seems to be in a rush all the time - no wonder that 
software often turns bad...  (Which just reminds me of a funny cartoon 
of the great Gary Larson where veggies "turn bad" in the fridge - with a 
pair of forks as weapons.) ;-)

Kind regards

	robert

[toc] | [prev] | [next] | [standalone]

#10522

On Sun, 4 Dec 2011 10:37:37 -0800 (PST), Lew <lewbloch@gmail.com>
wrote, quoted or indirectly quoted someone who said :

>Amazing what the documentation can reveal if one were *ACTUALLY TO READ IT*.

Why do you mean "IT"? The online docs on Java would form a book
several meters thick.  You can't read it all. You have to know WHAT to
read. You an almost supernatural skill at knowing where to look,
perhaps because you have read it all and remember where everything is
discussed. Others have not.

You assume everyone has your skill and energy for, and absolute
confidence in one's interpretation at reading documentation.

I had to read that page three times before I noticed the relevant
lines.  I only found it because someone had told me it HAD to be
there.  I was looking for "jar linking" or some similar phrase. It
wasn't  there.

My motive for asking is I was composing an entry in the java glossary
http://mindprod.com/jgloss/jarlinking.html

I did this as a favour to the Java community.  I did not do it to
annoy you.  When I write such an entry, I often ask a question to
check if there is anything I overlooked or if I harbour some
wrong-headed notion.

If you don't like answering, don't.  You are not obligated to respond.
But stop chastising me every time I ask a question.

It is perfectly legit to ask a question even if I am 99% certain of
the answer, just to bring up a topic for discussion and general
education. Stop pretending it is crime to ask a question.

Besides being rude, you are squelching newbies who are afraid of you.
When you attack me, you intimidating the newbies who fear the same
treatment.  You are interfering with education. CUT IT OUT!

The alternative would have resulted in a article that failed to
mention the option of OneJar or jar Class-path. That makes me brave
your shower of virtual vegetables almost every time I ask a question
or confirmation.  I have to go through this humiliation ritual for the
privilege of consulting the great Lew Oracle.

You have a serious psychological problem, a pathological desire to put
others down. It must poison your whole life. You could not possibly
maintain a relationship if you belittled your partner the way you
daily belittle me.

You are a very clever person, and the information you contribute is
invaluable, but please delete the sarcasm and hectoring.  It is a cold
wet blanket on discussion.
-- 
Roedy Green Canadian Mind Products
http://mindprod.com
For me, the appeal of computer programming is that
even though I am quite a klutz,
I can still produce something, in a sense
perfect, because the computer gives me as many
chances as I please to get it right.
 

[toc] | [prev] | [next] | [standalone]

#10533

Roedy Green <see_website@mindprod.com.invalid> writes:

> On Sun, 4 Dec 2011 10:37:37 -0800 (PST), Lew <lewbloch@gmail.com>
> wrote, quoted or indirectly quoted someone who said :
>
>>Amazing what the documentation can reveal if one were *ACTUALLY TO READ IT*.
>
> Why do you mean "IT"? The online docs on Java would form a book
> several meters thick.  You can't read it all. You have to know WHAT to
> read. You an almost supernatural skill at knowing where to look,
> perhaps because you have read it all and remember where everything is
> discussed. Others have not.

You can read it all. You just have to want to; and have the
stamina. Perhaps not watch television as much for a while.

>
> You assume everyone has your skill and energy for, and absolute
> confidence in one's interpretation at reading documentation.

I don't get the sense he thinks everyone has his skill or energy.

>
> I had to read that page three times before I noticed the relevant
> lines.  I only found it because someone had told me it HAD to be
> there.  I was looking for "jar linking" or some similar phrase. It
> wasn't  there.

So, are you saying that you would not understand it anyway, so there is
no point in reading it?

>
> My motive for asking is I was composing an entry in the java glossary
> http://mindprod.com/jgloss/jarlinking.html
>
> I did this as a favour to the Java community.  I did not do it to
> annoy you.  

Thank you. May the hordes of Java programmers come to your site and not
stackoverlow.com.

> When I write such an entry, I often ask a question to check if there
> is anything I overlooked or if I harbour some wrong-headed notion.

That is a good practise. But I am not sure what point you are making
about the suggestion that reading the documentation is a good thing.

>
> If you don't like answering, don't.  You are not obligated to respond.
> But stop chastising me every time I ask a question.

I am pretty confident that he knows he is not obligated to respond. In
fact you are not obligated to read his responses. But chastising you
seems quite sensible at the moment.

>
> It is perfectly legit to ask a question even if I am 99% certain of
> the answer, just to bring up a topic for discussion and general
> education. Stop pretending it is crime to ask a question.

I did not see anyone pretend such a thing.

>
> Besides being rude, you are squelching newbies who are afraid of you.
> When you attack me, you intimidating the newbies who fear the same
> treatment.  You are interfering with education. CUT IT OUT!

Why is being rude a bad thing? Sometimes its an excellent way to make a
point.

And why are you worrying about these scared little newbies that you are
projecting into the conversation? A newbie who is scared about being
corrected rudely; deserves to be frightened. 

But I disagree that he is intefering with education by suggesting that
people educate themselves (and in the end we only ever learn what we
teach ourselves). 

>
> The alternative would have resulted in a article that failed to
> mention the option of OneJar or jar Class-path. That makes me brave
> your shower of virtual vegetables almost every time I ask a question
> or confirmation.  I have to go through this humiliation ritual for the
> privilege of consulting the great Lew Oracle.

Not really. You are only creating the humiliation for yourself. There is
no requirement for you to read anything anyone posts. Choose who you
want to read and don't read what you don't want to read. 

>
> You have a serious psychological problem, a pathological desire to put
> others down. It must poison your whole life. You could not possibly
> maintain a relationship if you belittled your partner the way you
> daily belittle me.

Aww. shame. Perhaps a blankie and some nice warm milk?

>
> You are a very clever person, and the information you contribute is
> invaluable, but please delete the sarcasm and hectoring.  It is a cold
> wet blanket on discussion.

I disagree. I enjoy his wit.

--
a newbie

[toc] | [prev] | [next] | [standalone]

#10573

On Mon, 5 Dec 2011, ilAn wrote:

> Roedy Green <see_website@mindprod.com.invalid> writes:
>
>> My motive for asking is I was composing an entry in the java glossary
>> http://mindprod.com/jgloss/jarlinking.html
>>
>> I did this as a favour to the Java community.  I did not do it to
>> annoy you.
>
> Thank you. May the hordes of Java programmers come to your site and not
> stackoverlow.com.

Oi!

How about, may the hordes of Java programmers come to Roedy's site, and 
not to JavaRanch?

tom

-- 
I'd better quit my talking, 'cause I told you all I know. But please
remember, pardner, wherever you may go: the people are building a peaceful
world, and when the job is done, that'll be the biggest thing that man
has ever done.

[toc] | [prev] | [next] | [standalone]

#10540

On 12/5/2011 7:20 AM, Roedy Green wrote:
> On Sun, 4 Dec 2011 10:37:37 -0800 (PST), Lew<lewbloch@gmail.com>
> wrote, quoted or indirectly quoted someone who said :
>
>> Amazing what the documentation can reveal if one were *ACTUALLY TO READ IT*.
>
> Why do you mean "IT"? The online docs on Java would form a book
> several meters thick.  You can't read it all. You have to know WHAT to
> read. You an almost supernatural skill at knowing where to look,
> perhaps because you have read it all and remember where everything is
> discussed. Others have not.

????

This is a question about jar files.

The jar file specification linked to is about 450 lines.

The Java tutorials section about jar files which also
covers this is not that much longer.

I don't think it require supernatural skills to read
the jar file specification and the Java tutorials section
about jar files for a question about jar files!!

Arne

[toc] | [prev] | [next] | [standalone]

#10592 — OT: Was Re: Linking Jars

On 05/12/2011 12:20, Roedy Green wrote:
>
> You have a serious psychological problem, a pathological desire to put
> others down. It must poison your whole life. You could not possibly
> maintain a relationship if you belittled your partner the way you
> daily belittle me.
>

Don't worry, be happy.


The wizard of Java
==================

Cast
----

The Scarecrow: Roedy
The Tin-man: Lew
The Wizard: Lew
Glinda: Patricia?




Just my ¤0.02 worth.
-- 
RGB^H^H^HThe Lion

[toc] | [prev] | [next] | [standalone]

#10494

On Sun, 4 Dec 2011, Robert Klemme wrote:

> On 04.12.2011 05:00, Roedy Green wrote:
>> On Sat, 03 Dec 2011 19:53:37 -0800, Roedy Green
>> <see_website@mindprod.com.invalid>  wrote, quoted or indirectly quoted
>> someone who said :
>> 
>>> Are there any other options?
>> 
>> for example, is there something you can put in the main jar that
>> points to the second?
>
> Exactly.  And it would be my first choice.
>
> http://docs.oracle.com/javase/1.4.2/docs/guide/jar/jar.html#Main%20Attributes

The way Roedy's question so perfectly fits the solution makes me wonder if 
he's seen this before, but forgotten that he's seen it.

A word of warning about that Class-Path attribute. Say you write a library 
Aries which depends on two other libraries, Castor and Pollux. You ship a 
distribution with three jars, yours and those of the dependencies:

Aries
|
+- aries.jar
+- castor.jar
\- pollux.jar

In the manifest of aries.jar, you write a Class-Path attribute which 
refers to castor.jar and pollux.jar, and all is well.

Now i come along, with a project containing two modules, Odin and Thor, 
where Thor depends on Odin (that is, all the classes present in Odin are 
made available to Thor by my build and execution processes). Thor uses 
Aries. But Odin already uses Castor, for some purpose unrelated to Aries. 
My layout needs to look like this:

Odin
|
+- build/classes
|  |
|  \- Odin's own class files
|
+- lib
    |
    \- castor.jar

Thor
|
+- build/classes
|  |
|  \- Thor's own class files
|
+- lib
    |
    +- aries.jar
    \- pollux.jar

Note that Thor does not include castor.jar, because it is supplied by its 
dependency on Odin. All the libraries have the classes they need 
available, and all is well.

Except that aries.jar has a Class-Path entry saying there should be a 
castor.jar right next to it. Which there isn't. So, every time a tool 
which cares about Class-Path entries loads that jar, it will notice the 
absence, and moan about it. Sun's javac certainly does this - i have 
projects, with situations like the above, where half of the output is 
javac squawking about path problems which aren't problems at all. Luckily, 
i don't think java itself does.

If you think the above setup is overcomplex, how about a simpler one; one 
project, but where the different dependencies are kept in different 
folders, for clerical convenience:

Krishna
|
\- lib
    |
    +- Aries
    |  |
    |  +- aries.jar
    |  \- README
    |
    +- Castor
    |  |
    |  +- castor.jar
    |  \- castor-javadoc.zip
    |
    +- Pollux
       |
       +- castor.jar
       \- castor-extras.jar

Seems reasonable, right? And yet javac isn't going to like that at all.

The problem is that the Class-Path header expresses the dependency as a 
URL; a direct path that can be resolved in the filesystem. That constrains 
filesystem layout. It should have been a symbolic reference; perhaps a 
pairing of a Specification-Title and a Specification-Version that 
identifies what is needed, with the onus then being on the code loading 
the jar to go off and find that, by scanning the classpath, exploring the 
filesystem, looking in a module repository, etc. I think OSGi does 
something a bit like this; the JBoss 7 module system certainly does.

Or an even easier case - my new project Loki uses Aries, but i like naming 
my jars with a version number:

Loki
|
+- lib
    |
    +- aries-1.0.jar
    +- castor-1.4.jar
    \- pollux-2.2.1.jar

They're in the right place, but they have the wrong names. Cue javac 
complaining!

Having pointed out these problems, i feel like i should give some advice 
for what you should do. But i don't really know what you should do. 
Perhaps you should restrict the use of Class-Path to cases where you can 
control or predict the filesystem layout. Two cases spring to mind.

Firstly, where you have a library that is split into multiple jars, but 
where these will always be present together; perhaps you have a US tax 
rate library, where the code is updated occasionally, but the data for 
each state is updated frequently. You might have a jar for the code and a 
jar file for each state, containing classpath resources with data in. 
There, it would be reasonable to use a Class-Path in the code jar to drag 
in the state jars. This still falls over if i want to rename the jars, of 
course.

Secondly, where you are packaging for deployment as an application, not 
for further reuse. The main jar for an applet, application, or JWS app 
would all be good examples of this. Nobody but you will ever incorporate 
those jars into a project, so there is no worry about constaining 
filesystem layout.

Or just not worry about Class-Path, and rely on consumers to set up a 
classpath correctly.

tom

-- 
I GUARANTEE IT.

[toc] | [prev] | [next] | [standalone]

#10497

On 12/4/2011 12:25 PM, Tom Anderson wrote:

> The problem is that the Class-Path header expresses the dependency as a
> URL; a direct path that can be resolved in the filesystem.


I thought class path entries in the manifest file were always relative 
to the location of the containing Jar file?  I guess you could specify 
an absolute path, but I don't think it's required.

I didn't check the docs, but that's afaik.

[toc] | [prev] | [next] | [standalone]

#10572

On Sun, 4 Dec 2011, markspace wrote:

> On 12/4/2011 12:25 PM, Tom Anderson wrote:
>
>> The problem is that the Class-Path header expresses the dependency as a 
>> URL; a direct path that can be resolved in the filesystem.
>
> I thought class path entries in the manifest file were always relative to the 
> location of the containing Jar file?

Yep. They're relative URLs! The spec says

  Class-Path: The value of this attribute specifies the relative URLs of
  the extensions or libraries that this application or extension needs.
  URLs are separated by one or more spaces. The application or extension
  class loader uses the value of this attribute to construct its internal
  search path.

> I guess you could specify an absolute path, but I don't think it's 
> required.

Indeed it's not. But a relative URL is still a URL.

tom

-- 
I'd better quit my talking, 'cause I told you all I know. But please
remember, pardner, wherever you may go: the people are building a peaceful
world, and when the job is done, that'll be the biggest thing that man
has ever done.

[toc] | [prev] | [next] | [standalone]

#10500

On 12/4/11 04:53 , Roedy Green wrote:

> Are there any other options?

http://one-jar.sourceforge.net/

[toc] | [prev] | [standalone]

Back to top | Article view | comp.lang.java.programmer

csiph-web