when paranamer fails, fail over to using java reflection (#566)

Author: pjfanning

src/main/scala/com/fasterxml/jackson/module/scala/introspect/JavaParameterIntrospector.scala

@@ -1,23 +1,29 @@
 package com.fasterxml.jackson.module.scala.introspect
 
-import java.lang.reflect.{Constructor, Field, Method, Parameter}
-
 import com.thoughtworks.paranamer.{BytecodeReadingParanamer, CachingParanamer}
 
+import java.lang.reflect.{Constructor, Field, Method, Parameter}
+import scala.util.Try
+
 private[introspect] object JavaParameterIntrospector {
 
   private val paranamer = new CachingParanamer(new BytecodeReadingParanamer)
 
   def getCtorParamNames(ctor: Constructor[_]): IndexedSeq[String] = {
-    paranamer.lookupParameterNames(ctor, false).toIndexedSeq
+    Try(paranamer.lookupParameterNames(ctor, false))
+      .getOrElse(ctor.getParameters.map(_.getName))
+      .toIndexedSeq
   }
 
   def getMethodParamNames(mtd: Method): IndexedSeq[String] = {
-    paranamer.lookupParameterNames(mtd, false).toIndexedSeq
+    Try(paranamer.lookupParameterNames(mtd, false))
+      .getOrElse(mtd.getParameters.map(_.getName))
+      .toIndexedSeq
   }
 
   def getFieldName(field: Field): String = {
-    paranamer.lookupParameterNames(field, false).headOption.getOrElse(None.orNull)
+    Try(paranamer.lookupParameterNames(field, false).headOption.getOrElse(None.orNull))
+      .getOrElse(field.getName)
   }
 
   def getParameterName(parameter: Parameter): String = parameter.getName