/usr/share/proton-0.14.0/examples/java/messenger/ is in libqpid-proton8-dev-examples 0.14.0-5.1ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/share/proton-0.14.0/examples/java/messenger/README.txt
/usr/share/proton-0.14.0/examples/java/messenger/pom.xml
/usr/share/proton-0.14.0/examples/java/messenger/recv
/usr/share/proton-0.14.0/examples/java/messenger/send
/usr/share/proton-0.14.0/examples/java/messenger/src/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/qpid/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/qpid/proton/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/qpid/proton/example/
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/qpid/proton/example/Recv.java
/usr/share/proton-0.14.0/examples/java/messenger/src/main/java/org/apache/qpid/proton/example/Send.java