The attach listener file, usually /tmp/.java_pid<pid> is created from the hotspot JVM process. In most cases it will belong to the process effective user and effective group. However, there can be cases when this will not happen, e.g. when the directory where it is created has set the s-bit for its group. Then the group of the directory is taken. Such situations will cause errors when the attach client tries to connect and it is checked whether the group of the attach file matches the client processes' effective group.

JDK-7152800 already fixes this issue for MacOS, where new files by default belong to the group of the directory rather than that of the process.