java - Difference of List and ArrayList in declaration? -

this question has answer here:

• type list vs type arraylist in java 14 answers
• list versus arraylist reference type? 3 answers

is there difference between these two? if so, it?

list<integer> x = new arraylist<integer>(); 

and

arraylist<integer> x = new arraylist<integer>(); 

the first declaration lets program interface. ensures later on can safely replace arraylist with, say, linkedlist, , rest of code going compile.

the second declaration lets program class, potentially use methods of arraylist not implement list interface. example, can call ensurecapacity() on list declared arraylist, not on list declared list. although programming interface should preferred, there nothing wrong doing if must call class-specific methods: example, ability call ensurecapacity() save unnecessary reallocations if know new target size of list.