Force Java 8 as we cannot build with Java 11 due to upstream bug.

Signed-off-by: Roland Grunberg <rgrunber@redhat.com>

jctools.spec

@@ -3,12 +3,13 @@
 
 Name:          jctools
 Version:       2.1.2
-Release:       6%{?dist}
+Release:       7%{?dist}
 Summary:       Java Concurrency Tools for the JVM
 License:       ASL 2.0
 URL:           http://jctools.github.io/JCTools/
 Source0:       https://github.com/JCTools/JCTools/archive/v%{namedversion}/%{name}-%{namedversion}.tar.gz
 
+BuildRequires:  java-1.8.0-openjdk-devel
 BuildRequires:  maven-local
 BuildRequires:  mvn(com.github.javaparser:javaparser-core)
 BuildRequires:  mvn(com.google.guava:guava-testlib)
@@ -109,6 +110,8 @@ done
 %mvn_package :jctools-build __noinstall
 
 %build
+# https://github.com/JCTools/JCTools/issues/254 (Unsafe.defineClass)
+export JAVA_HOME=%{_jvmdir}/java-1.8.0
 %mvn_build -s
 
 %install
@@ -129,6 +132,9 @@ done
 %license LICENSE
 
 %changelog
+* Fri Jun 26 2020 Roland Grunberg <rgrunber@redhat.com> - 2.1.2-7
+- Force Java 8 as we cannot build with Java 11 due to upstream bug.
+
 * Wed Jan 29 2020 Fedora Release Engineering <releng@fedoraproject.org> - 2.1.2-6
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_32_Mass_Rebuild