title: What is "~[task/:na]" or "~[na:na]" in a Java stack trace?
body: <p>Java stack traces in AWS Lambda now include some extraneous new stuff at the end of each line:</p>
  
  <pre><code>at com.cth.rets.indexer.App.lambda$0(App.java:53) [task/:na]
  at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:792) ~[task/:na]
  at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:776) ~[task/:na]
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[task/:na]
  at com.cth.rets.indexer.App.lambdaHandler(App.java:47) [task/:na]
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
  at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
  at lambdainternal.EventHandlerLoader$StreamMethodRequestHandler.handleRequest(EventHandlerLoader.java:350) ~[na:na]
  at lambdainternal.EventHandlerLoader$2.call(EventHandlerLoader.java:888) ~[na:na]
  at lambdainternal.AWSLambda.startRuntime(AWSLambda.java:293) ~[na:na]
  at lambdainternal.AWSLambda.&lt;clinit&gt;(AWSLambda.java:64) ~[na:na]
  at java.lang.Class.forName0(Native Method) ~[na:1.8.0_181]
  at java.lang.Class.forName(Class.java:348) ~[na:1.8.0_181]
  at lambdainternal.LambdaRTEntry.main(LambdaRTEntry.java:104) ~[LambdaJavaRTEntry-1.0.jar:na]
  </code></pre>
  
  <p>What do all the little extra <code>~[...]</code> things mean?</p>