Group is required or a null pointer exception occurs.

[ZeroEcks]

If you set this up with a new user pool and try to use it with no groups, a null pointer exception occurs.

2018-09-24 13:31:22.446 ERROR 50885 --- [nio-8080-exec-1] .c.b.f.AwsCognitoJwtAuthenticationFilter : Error occured while processing Cognito ID Token

java.lang.NullPointerException: null
	at com.ixortalk.aws.cognito.boot.filter.AwsCognitoIdTokenProcessor.convertList(AwsCognitoIdTokenProcessor.java:109) ~[ixortalk.aws.cognito.jwt.security.filter-0.0.7.jar:0.0.7]
	at com.ixortalk.aws.cognito.boot.filter.AwsCognitoIdTokenProcessor.getAuthentication(AwsCognitoIdTokenProcessor.java:83) ~[ixortalk.aws.cognito.jwt.security.filter-0.0.7.jar:0.0.7]
	at com.ixortalk.aws.cognito.boot.filter.AwsCognitoJwtAuthenticationFilter.doFilter(AwsCognitoJwtAuthenticationFilter.java:54) ~[ixortalk.aws.cognito.jwt.security.filter-0.0.7.jar:0.0.7]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:116) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:105) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:334) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:215) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:178) [spring-security-web-5.0.8.RELEASE.jar:5.0.8.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:357) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:270) [spring-web-5.0.9.RELEASE.jar:5.0.9.RELEASE]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:728) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.ApplicationDispatcher.processRequest(ApplicationDispatcher.java:472) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.ApplicationDispatcher.doForward(ApplicationDispatcher.java:395) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.ApplicationDispatcher.forward(ApplicationDispatcher.java:316) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:395) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:254) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:177) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:800) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:806) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1498) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135) [na:na]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) [na:na]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.34.jar:8.5.34]
	at java.base/java.lang.Thread.run(Thread.java:844) [na:na]

This is fixed by creating a group.

Would be nice if it was a little more clear whats wrong with this?

[isarang]

You are missing out an use case where a user can be without groups.
Add a null check and return empty collection at https://github.com/IxorTalk/ixortalk.aws.cognito.jwt.security.filter/blob/master/src/main/java/com/ixortalk/aws/cognito/boot/filter/AwsCognitoIdTokenProcessor.java#L109

[aburnett]

covered by PR #19