Explicitly specify JVM source and target version

regexp.spec

@@ -1,7 +1,7 @@
 Name:           regexp
 Epoch:          1
 Version:        1.5
-Release:        39%{?dist}
+Release:        40%{?dist}
 Summary:        Simple regular expressions API
 License:        ASL 2.0
 URL:            http://jakarta.apache.org/%{name}/
@@ -55,7 +55,7 @@ EOF
 
 %build
 mkdir lib
-%ant -Djakarta-site2.dir=. jar javadocs
+%ant -Djakarta-site2.dir=. -Dant.build.javac.source=1.7 -Dant.build.javac.target=1.7 jar javadocs
 
 %mvn_artifact pom.xml build/*.jar
 
@@ -72,6 +72,9 @@ mkdir lib
 %doc LICENSE
 
 %changelog
+* Fri Aug 05 2022 Marian Koncek <mkoncek@redhat.com> - 1:1.5-40
+- Explicitly specify JVM source and target version
+
 * Sat Jul 23 2022 Fedora Release Engineering <releng@fedoraproject.org> - 1:1.5-39
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_37_Mass_Rebuild