It just make the default-jre installation explicit:
```
vsellier@kafka1 ~ % aptitude why default-jre-headless
i zookeeper Depends default-jre-headless | java6-runtime-headless
```
```
*** Running octocatalog-diff on host kafka1diff origin/production/journal0.internal.staging.swh.network current/journal0.internal.softwareheritage.orgstaging.swh.network
I, [2020-11-19T15:19:48.690350 #29692] INFO -- : Catalogs compiled for kafka1.internal.softwareheritage.org*******************************************
I, [2020-11-19T15:19:49.598564 #29692] INFO -- : Diffs computed for kafka1.internal.softwareheritage.org+ Anchor[java::begin:]
diff origin/production/kafka1.internal.softwareheritage.org current/kafka1.internal.softwareheritage.org*******************************************
+ Anchor[java::end]
*******************************************
+ Exec[update-java-alternatives] =>
parameters =>
"command": "update-java-alternatives --set java-1.11.0-openjdk-amd64 --jre-h...
"path": "/usr/bin:/usr/sbin:/bin:/sbin",
"unless": "test /etc/alternatives/java -ef '/usr/lib/jvm/java-1.11.0-openjdk...
*******************************************
+ File_line[java-home-environment] =>
parameters =>
"line": "JAVA_HOME=/usr/lib/jvm/java-1.11.0-openjdk-amd64/",
"match": "JAVA_HOME=",
"path": "/etc/environment"
*******************************************
+ Package[default-jre-headless] =java-common] =>
parameters =>
"ensure": "present"
*******************************************
*** End octocatalog-diff on kafka1.internal.softwareheritage.org+ Package[java] =>
parameters =>
"ensure": "present",
"name": "openjdk-11-jre-headless"
*******************************************
*** End octocatalog-diff on journal0.internal.staging.swh.network
```
```
```*** Running octocatalog-diff on host journal0diff origin/production/kafka1.internal.softwareheritage.org current/kafka1.internal.staging.swh.networksoftwareheritage.org
*******************************************
I, [2020-11-19T15:20:16.689247 #2996] INFO -- : Catalogs compiled for journal0.internal.staging.swh.network+ Anchor[java::begin:]
I, [2020-11-19T15:20:17.532826 #2996] INFO -- : Diffs computed for journal0.internal.staging.swh.network*******************************************
diff origin/production/journal0.internal.staging.swh.network current/journal0.internal.staging.swh.network+ Anchor[java::end]
*******************************************
+ Exec[update-java-alternatives] =>
parameters =>
"command": "update-java-alternatives --set java-1.11.0-openjdk-amd64 --jre-h...
"path": "/usr/bin:/usr/sbin:/bin:/sbin",
"unless": "test /etc/alternatives/java -ef '/usr/lib/jvm/java-1.11.0-openjdk...
*******************************************
+ File_line[java-home-environment] =>
parameters =>
"line": "JAVA_HOME=/usr/lib/jvm/java-1.11.0-openjdk-amd64/",
"match": "JAVA_HOME=",
"path": "/etc/environment"
*******************************************
+ Package[default-jre-headless] =java-common] =>
parameters =>
"ensure": "present"
*******************************************
+ Package[java] =>
parameters =>
"ensure": "present",
"name": "openjdk-11-jre-headless"
*******************************************
*** End octocatalog-diff on journal0kafka1.internal.staging.swh.networkoftwareheritage.org
```