RFR 8181299/10, Several jdk tests fail with java.lang.NoClassDefFoundError: jdk/test/lib/process/StreamPumper
ioi.lam at oracle.com
Fri Jun 2 16:14:19 UTC 2017
On 6/2/17 8:44 AM, Ioi Lam wrote:
> On 6/2/17 6:40 AM, Chris Hegarty wrote:
>> On 02/06/17 00:14, Ioi Lam wrote:
>>> The gem is hidden in the compile.0.jta file. It contains something
>>> -sourcepath <blahblah>:/jdk/foobar/test/lib:<blahblah>
>>> So if my test refers to a class under /test/lib, such as
>>> jdk.test.lib.process.ProcessTools, javac will be able to locate it
>>> /jdk/foobar/test/lib/jdk/test/lib/process/ProcessTools.java, and will
>>> build it automatically.
>>> So really, there's no reason why the test must explicitly do an @build
>>> of the library classes that it uses.
>> Sure, you're relying on the implicit compilation of dependencies
>> by javac. Look at the output, where it compiles the library
>> classes to. It is part of the classes directory for the
>> individual test. That means that the library classes will need
>> to be compiled many many times. The @build tag will compile
>> the library classes to a common output directory, where they
>> can be reused ( unless I'm missing something ).
> Yes, @build will compile classes so that they can be reused. But why
> should it be the responsibility of every test to do this?
> To reuse my malloc metaphore -- is it reasonable for every program
> that uses malloc to explicitly build libc?
> By the way, jtreg arranges the output directory of the test by the
> directory they sit in, so
> will all output their .class files to the same directory. Therefore,
> the amount of duplicated classes is not as bad as you might think.
> We've been omitting the @build tags in the hotspot tests and we
> haven't seen any problems.
> - Ioi
To avoid repeat compilation of the library classes, a more reasonable
solution would be:
 Before test execution -- scan all the selected test to find all
libraries specified by @library tags
 Fully compile all the libraries into their own output directories
 Then, start execution of the selected tests
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