/usr/lib/gcc-cross/s390x-linux-gnu/4.9/ecj1 is in gcj-4.9-s390x-linux-gnu 4.9.3-13ubuntu2cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/s390x-linux-gnu/4.9/../../../gcc/x86_64-linux-gnu/4.9/ecj1