clarification in Oracle Certified Professional Java SE 8 Programmer II Study Guide (Sybex)

[Ramya R Subramanian]

The errata for page 159, for the first row in the table 3.12 is a little bit confusing.It says "Add key to map" . But the key is already in the map right ? So should it just say something like key is updated/associated with Value passed the merge method.Like below

BiFunction<String,String,String> mapper= (v1,v2)->null;
		Map<String,String> favorites= new HashMap<>();
		favorites.put("Joe", null);
		favorites.merge("Joe", "skyride", mapper);
		System.out.println(favorites);//{Joe=skyride}

In page 339 , table under the invokeAll description it says, "Executes the given tasks, synchronously returning the results of all tasks as a Collection of Future Object.Here Collection(Interface) is a very generic term which has List,Set,Queue ..etc. But here the invokeAll returns only List.So Collection here can be replaced with List of future objects. (as specified in the method signature and also in the next page).

In page 135 , in the last para above the table it says "luckily there are only seven methods"..but there are eight methods in the table

[Jeanne Boyarsky]

Ramya Subraamanian wrote:The errata for page 159, for the first row in the table 3.12 is a little bit confusing.It says "Add key to map" . But the key is already in the map right ?

That's fair. I changed it to ""Update key's value in map"

Ramya Subraamanian wrote:In page 339 , table under the invokeAll description it says, "Executes the given tasks, synchronously returning the results of all tasks as a Collection of Future Object.Here Collection(Interface) is a very generic term which has List,Set,Queue ..etc. But here the invokeAll returns only List.So Collection here can be replaced with List of future objects. (as specified in the method signature and also in the next page).

That Collection is referring to the parameters that are passed in rather than returned. "take" is intended to convey "take as a parameter". Which is a Collection rather than a List.

Ramya Subraamanian wrote:In page 135 , in the last para above the table it says "luckily there are only seven methods"..but there are eight methods in the table

Confirmed and logged in errata

[Ramya R Subramanian]

Jeanne Boyarsky wrote:That Collection is referring to the parameters that are passed in rather than returned. "take" is intended to convey "take as a parameter". Which is a Collection rather than a List.

its a bit confusing because it says "returning the results of all tasks as Collection"here..and I don't see a word "take" here. I have a hard copy of the book

Executes the given tasks, synchronously returning the results of all tasks as a Collection of Future objects, in the same order they were in the original collection.

[Jeanne Boyarsky]

Oh! *in* the table. I was looking under the table. You are correct.