Reports on declarations of Collection variables made by using the collection class as the type, rather than an appropriate interface.
Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>
Reports Collection.addAll() and Map.putAll() calls after instantiation of a collection using a constructor call without arguments. Such constructs can be replaced with a single call to a parametrized constructor which simplifies code. Also for some collections the replacement might be more performant.
Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>
There are two styles to convert a collection to an array: either using a pre-sized array (like c.toArray(new String[c.size()])) or using an empty array (like c.toArray(new String[0]).
In older Java versions using pre-sized array was recommended, as the reflection call which is necessary to create an array of proper size was quite slow. However since late updates of OpenJDK 6 this call was intrinsified, making the performance of the empty array version the same and sometimes even better, compared to the pre-sized version. Also passing pre-sized array is dangerous for a concurrent or synchronized collection as a data race is possible between the size and toArray call which may result in extra nulls at the end of the array, if the collection was concurrently shrunk during the operation.
Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>
Reports while loops which iterate over collections, and can be replaced with an enhanced for loop (i.e. foreach iteration syntax).
Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>
Reports for loops which iterate over collections or arrays, and can be replaced with an enhanced for loop (i.e. the foreach iteration syntax).
Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>
Alexander Kriegisch
Lars Grefer
Andy Clement