StringBuffer is a legacy synchronized class. StringBuilder is a direct replacement to StringBuffer which generally have better performance.

This was required by the Eclipse team as one precondition for the next
release.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

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>

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>

Prior to this AspectJ would discard ignore the ClasspathEntry
objects built by JDT and just work with the classpath as a string,
driving the JDT FileSystem to rebuild classpath entries again at
a later date using the string. This is more complex in Java9 because
the string representation was losing whether some entries came in
via modulepath.  ClasspathEntry construction for modulepath entries
is non trivial (since the module-info must be processed).

The new version will cache some of the ClasspathEntry objects (those
built for modulepaths) and do more work on the AspectJ side building
classpath entries in general. It now passes these entries to a
different FileSystem entry point rather than the entry point that
takes a string path.

Signed-off-by: hsestupin <stupin.sergey@gmail.com>