As I recall, before Java 8, the default capacity of ArrayList was 10.
Surprisingly, the comment on the default (void) constructor still says: Cons
ArrayList default size in JAVA 8 is stil 10. The only change made in JAVA 8 is that if a coder adds elements less than 10 then the remaining arraylist blank places are not specified to null. Saying so because I have myself gone through this situation and eclipse made me look into this change of JAVA 8.
You can justify this change by looking at below screenshot. In it you can see that ArrayList size is specified as 10 in Object[10] but the number of elements displayed are only 7. Rest null value elements are not displayed here. In JAVA 7 below screenshot is same with just a single change which is that the null value elements are also displayed for which the coder needs to write code for handling null values if he is iterating complete array list while in JAVA 8 this burden is removed from the head of coder/developer.
Screen shot link.