在Android Studio中包含iTextG时出现以下错误，

com.android.dex.DexException: Multiple dex files define Lcom/itextpdf/awt/geom/AffineTransform;
    at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:596)
    at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:554)
    at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:535)
    at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:171)
    at com.android.dx.merge.DexMerger.merge(DexMerger.java:189)
    at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:454)
    at com.android.dx.command.dexer.Main.runMonoDex(Main.java:303)
    at com.android.dx.command.dexer.Main.run(Main.java:246)
    at com.android.dx.command.dexer.Main.main(Main.java:215)
    at com.android.dx.command.Main.main(Main.java:106)

我不知道为什么，但似乎这个库中也有awt。这就是我包括的方式：

1. 从http://sourceforge.net/projects/itextg/下载itextg
2. 提取jar文件
3. 将itextg-5.5.4.jar复制到app目录中的libs文件夹
4. 摇篮清洁

为什么awt仍在库中？