/usr/lib/gcc-cross/aarch64-linux-gnu/4.8/ecj1 is in gcj-4.8-aarch64-linux-gnu 4.8.2-13ubuntu1cross0.11.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/aarch64-linux-gnu/4.8/../../../gcc/x86_64-linux-gnu/4.8/ecj1