Package: jtreg
Version: 4.2-b13-1
Severity: important
Dear Maintainer,
openjdk-9 introduced a few api changes that result in runtime errors when
trying to run the java classes under openjdk 8 (or earlier) even when
-source/-target are properly set.
The fix is to build such code using the new openjdk-9 flag "--release" instead
of the "-source/-target" pair.
When running Cosmic's jtreg 4.2-b13-1 with agentvm under openjdk-8 it will fail
and output a few lines such as:
stderr: Exception: java.lang.NoSuchMethodError thrown from the
UncaughtExceptionHandler in thread "main"
The java.lang.NoSuchMethodError is actually caused by
"java.lang.NoSuchMethodError: java.nio.ByteBuffer.flip()Ljava/nio/ByteBuffer"
which can be easily solved by building jtreg with the "--release 7" argument.
[Test Case]
For this test case we need to create an empty TEST.ROOT file and a test class
to satisfy jtreg requirements of a minimum test. jtreg must also be forced to
use openjdk-8.
$ sudo apt install openjdk-8-jdk jtreg
$ touch TEST.ROOT
$ cat > Hello.java << EOF
/*
* @test
* @bug 2718282
* @summary Hello test
*/
public class Hello {
public static void main(String [] args) throws Exception {
if (true)
System.out.println("Hello World!");
else
throw new Exception("??");
}
}
EOF
$ JT_JAVA=/usr/lib/jvm/java-8-openjdk-amd64/ jtreg -va -agentvm Hello.java
[2018-11-15 23:42:34,720] Agent[0]: stderr:
[2018-11-15 23:42:34,721] Agent[0]: stderr: Exception:
java.lang.NoSuchMethodError thrown from the UncaughtExceptionHandler in thread
"main"
--------------------------------------------------
TEST: Hello.java
TEST JDK: /usr/lib/jvm/java-8-openjdk-amd64
[snipped]
Test results: error: 1
Report written to /tmp/JTreport/html/report.html
Results written to /tmp/JTwork
Error: Some tests failed or other problems occurred.
The expected response from jtreg does not contain the "stderr:" lines as in:
$ JT_JAVA=/usr/lib/jvm/java-8-openjdk-amd64/ jtreg -va -agentvm Hello.java
--------------------------------------------------
TEST: Hello.java
TEST JDK: /usr/lib/jvm/java-8-openjdk-amd64
[snipped]
Test results: passed: 1
Report written to /tmp/JTreport/html/report.html
Results written to /tmp/JTwork
Alternatively one can also check that openjdk-lts is not affected by the
change, it should output the same before and after the fix:
$ sudo apt install openjdk-11-jdk
$ JT_JAVA=/usr/lib/jvm/java-11-openjdk-amd64/ jtreg -va -agentvm Hello.java
--------------------------------------------------
TEST: Hello.java
TEST JDK: /usr/lib/jvm/java-11-openjdk-amd64
[snipped]
Test results: passed: 1
Report written to /tmp/JTreport/html/report.html
Results written to /tmp/JTwork
[Regression Potential]
1. The --release argument is jdk9+ only, if jtreg is ever build with an older
jdk it will FTBFS, so this change should only be backported on releases where
the default-jdk is 9+.
2. The --release N argument is equivalent to setting -source N/-target
N/-bootclasspath <N bootclasspath>, which can cause issues if the compiled
classes use APIs that have been removed or are considered internal. The current
jtreg version does not rely on internal classes from jdk 8 (otherwise it would
FTBFS) but if a later version does that it will probably FTBFS - note that this
is very unlikely as it would mean that upstream decided to break building jtreg
with newer jdks.
[Other Info]
See https://github.com/apache/felix/pull/114 for a good overview on the methods
that changed on OpenJDK 9 and a better description on the cause. Note that they
propose patching the methods to cast ByteBuffer to Buffer when calling the
affected methods, but this can be easily prevented by using the --release
argument instead.
I will follow-up with a patch as soon as I have a bug # to put on the
changelog and the patch dep3 header.
Regards,
Tiago
-- System Information:
Debian Release: buster/sid
APT prefers disco
APT policy: (500, 'disco'), (400, 'disco-proposed')
Architecture: amd64 (x86_64)
Kernel: Linux 4.18.0-10-generic (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US
(charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
