Closes #148.

TODO: Should more AJDE stuff be removed?
Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

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

It means that separate File.exists() check before File.isDirectory() check is redundant.

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

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

In two places, the documentation now contains this text:

"Since AspectJ 1.9.7, the obsolete Oracle/BEA JRockit agent is no longer
part of AspectJ. JRockit JDK never supported Java versions higher than
1.6. Several JRockit JVM features are now part of HotSpot and tools like
Mission Control available for OpenJDK and Oracle JDK."

The decision to drop JRockit support was made during a discussion
between Alexander Kriegisch and Andy Clement:

Andy Clement wrote on 26 Mar 2021:

> Yes I think so.
>
>
> Alexander Kriegisch wrote on 26 Mar 2021:
>
>> https://en.wikipedia.org/wiki/JRockit
>>
>> Can we get rid of that? AspectJ requires Java 8, JRockit never
>> supported more than Java 6.

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

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

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

Those versions were not detected until now, which lead to bogus Windows
batch files forwarding only 9 Ajc parameters to the Java process via
"%1 %2 %3 %4 %5 %6 %7 %8 %9" instead of "%*".

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

Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>

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 calls to Collections.sort(list, comparator) which could be replaced with list.sort(comparator).

Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>

Signed-off-by: Lars Grefer <eclipse@larsgrefer.de>

Reports any String.indexOf() expressions which can be replaced with a call to the String.contains() method available in Java 5 and newer.

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>

- reduced build level from 8 to 7 so that the weaver can be used on Java7.
- minor readme tweaks