Use maximum compression, jacocoant.jar isn't a bundle.
diff --git a/org.jacoco.build/buildbundle.xml b/org.jacoco.build/buildbundle.xml
index c06a36f..514f231 100644
--- a/org.jacoco.build/buildbundle.xml
+++ b/org.jacoco.build/buildbundle.xml
@@ -56,7 +56,7 @@
<target name="package" if="do.package" depends="compile,runcustompackage,manifest">
<property name="result.dist.bundle.jar.file" location="${result.dist.lib.dir}/${manifest.Bundle-SymbolicName}_${qualified.bundle.version}.jar"/>
<mkdir dir="${result.dist.lib.dir}"/>
- <jar destfile="${result.dist.bundle.jar.file}" manifest="${result.temp.bundle.manifest.file}">
+ <jar destfile="${result.dist.bundle.jar.file}" manifest="${result.temp.bundle.manifest.file}" level="9">
<fileset dir="${result.tmp.bundle.classes.dir}"/>
<fileset file="${source.bundle.dir}/about.html"/>
</jar>