Re: How to print out the currently used JAR file path to verify it is using right JAR?

From:

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <arne@vajhoej.dk>

Newsgroups:

comp.lang.java.programmer

Date:

Sun, 06 Nov 2011 17:42:29 -0500

Message-ID:

<4eb70d56$0$287$14726298@news.sunsite.dk>

On 10/7/2011 9:56 AM, www wrote:

My Java program running on linux machines fails on the code which is
using 3rd party JAR file. The error message suggest that it is
probably using an old version JAR file which I am not aware where it
is. If it is using the NEW jar file, the program should pass.

I hope to add some printing statements in the code to show the JAR
file name and path right before the code crashes. Is there a way to do
it?

The classpath should be explicit (no CLASSPATH env var) and so simple
or at least structured that it should not be a problem to know
where classes are loaded from.

There are several ways of getting the location of the
Foobar class:

Foobar.class.getProtectionDomain().getCodeSource().getLocation().getPath()

Foobar.class.getClassLoader().getResource("Path.class").getPath()

But to avoid future problems may I suggest that you in the
startup code find the jar for some of the critical libs
and check the version and if it is too old then you
print location and version and exit.

JarFile jar = new JarFile(fullfnm);
Manifest mf = jar.getManifest();
String ver = mf.getEntries().get(name).getValue("Implementation-Version");

should get a version number from the jar file for a
properly build jar file.

Arne