Paranamer 2.8 on Java 8 causes "Parameter names not found" error

[tribbloid]

Paranamer hasn't been updated for a very long time and is now causing all kinds of trouble in later Java versions, its time to finally drop it and uses the much more stable Java reflection for the same purpose.

When running the following code:

  case class TimeWrapper(time: Date)

    val clazz = classOf[TimeWrapper]
    val tors = clazz.getConstructors
    val ctor = tors.head
    val exe = new Executable(ctor)

    val names = ParanamerReader.lookupParameterNames(exe)

    require(names.size == 1)

Paranamer throw the following error:

Parameter names not found for <init>
com.thoughtworks.paranamer.ParameterNamesNotFoundException: Parameter names not found for <init>
	at com.thoughtworks.paranamer.BytecodeReadingParanamer$TypeCollector.getParameterNamesForMethod(BytecodeReadingParanamer.java:241)
	at com.thoughtworks.paranamer.BytecodeReadingParanamer$TypeCollector.access$300(BytecodeReadingParanamer.java:144)
	at com.thoughtworks.paranamer.BytecodeReadingParanamer.lookupParameterNames(BytecodeReadingParanamer.java:104)
	at com.thoughtworks.paranamer.CachingParanamer.lookupParameterNames(CachingParanamer.java:90)
	at com.thoughtworks.paranamer.CachingParanamer.lookupParameterNames(CachingParanamer.java:83)
	at org.json4s.reflect.package$ParanamerReader$.lookupParameterNames(package.scala:92)
	at org.apache.spark.ml.dsl.utils.messaging.MessageReaderSuite.$anonfun$new$3(MessageReaderSuite.scala:34)
...

Test was conducted on Java 8, it is unknown whether it can be triggered reliably

json4s version

4.0.4

scala version

2.12.16

jdk version

OpenJDK 8

[magnolia-k]

d0781fe

[tribbloid]

Thanks a lot! Turns out that the old paranamer depends on metadata from the "-g:vars" compiler argument to work, but this is a huge reduction of vulnerability!