> [T]he default implementation of Java’s java.util.Arrays.sort() and java.util.Collection.sort() method [...] is based on a complex combination of merge sort and insertion sort. It had a bug history, but was reported as fixed as of Java version 8. We decided to verify the implementation [...] we discovered that the fix to the bug mentioned above is in fact not working. We succeeded to characterize the conditions under which the bug occurs and results in a crash [...]