[Bug] NPE while decompiling jar files with --enable-file-content

[skirge]

Describe the bug
NPE can occur if JAR file contains files other than .class (.xml for example)

To Reproduce
jimple2cpg -J-Xmx32G dir-with-jars --enable-file-content --output cpg.bin.zip

I forgot to save stacktrace, sorry.

This fixed it for me:

diff --git a/joern-cli/frontends/jimple2cpg/src/main/scala/io/joern/jimple2cpg/util/Decompiler.scala b/joern-cli/frontends/jimple2cpg/src/main/scala/io/joern/jimple2cpg/util/Decompiler.scala
index 58a96003f..9b08e2546 100644
--- a/joern-cli/frontends/jimple2cpg/src/main/scala/io/joern/jimple2cpg/util/Decompiler.scala
+++ b/joern-cli/frontends/jimple2cpg/src/main/scala/io/joern/jimple2cpg/util/Decompiler.scala
@@ -51,7 +51,7 @@ class Decompiler(classFile: List[File]) {
             val className = s.toString.split(" ").last
             logger.debug(s"Decompiling class '$className'")
           case OutputSinkFactory.SinkType.EXCEPTION =>
-            logger.error(s.toString)
+            logger.error(String.valueOf(s))
           case _ => // ignore
       }
     }