Ignoring InnerClasses attribute for an anonymous inner class

[MWNemesis]

Hi Gradle give me the following warning:

warning: Ignoring InnerClasses attribute for an anonymous inner class
(com.itextpdf.text.pdf.MappedRandomAccessFile$1) that doesn\u0027t come with an
associated EnclosingMethod attribute. This class was probably produced by a
compiler that did not target the modern .class file format. The recommended
solution is to recompile the class from source, using an up-to-date compiler
and without specifying any "-target" type options. The consequence of ignoring
this warning is that reflective operations on this class will incorrectly
indicate that it is not an inner class.

warning: Ignoring InnerClasses attribute for an anonymous inner class
(com.itextpdf.text.pdf.events.IndexEvents$1) that doesn\u0027t come with an
associated EnclosingMethod attribute. This class was probably produced by a
compiler that did not target the modern .class file format. The recommended
solution is to recompile the class from source, using an up-to-date compiler
and without specifying any "-target" type options. The consequence of ignoring
this warning is that reflective operations on this class will incorrectly
indicate that it is not an inner class.

Wich solution can be applied?