Spring Boot startup slow on Raspberry PI - performance

Question

Using Spring Boot 2 for an IoT application, I notice that the startup time for Spring is disproportionally slow. The platform is a Raspberry PI 2B - of course, this is going to be significantly slower than a PC. For normal code execution I measure a 20x to 50x difference.
Spring boot startup time on my PC (Win10 x64): 5 seconds
Spring boot startup time on the PI (Ubuntu Server, ARM java in docker running a jar): 11 minutes
If I use the highest factor I've ever measured (50x), I would expect to see a startup time of less than half of the current state. So far, I tried:
Excluding dependencies from auto configuration (now minimal with only only spring-boot-starter-web, kotlin, undertow, webflux, reactor and kafka)
Logging on DEBUG to see what was happening during quiet periods (mostly beans being set up, nothing suspicious, though some beans take several seconds to load)
Different docker image for Java on ARM (no effect)
CPU is consistently at 100%, memory is around 20% and there is plenty of disk space
My preliminary conclusion is that loading beans eats all the CPU cycles. I imagine that initializing a bean should not take several seconds, but it does. What could be the bottleneck here? Can I get Spring to load faster in any way?
Here is the first part of the output from a PC:
2018-01-06 13:43:03.462 INFO 9144 --- [ main] c.e.b.BasestationApplicationKt : Starting BasestationApplicationKt on GPC with PID 9144 (C:\Data\Code\app\git\basestation\out\production\classes started by User in C:\Data\Code\app\git)
2018-01-06 13:43:03.471 INFO 9144 --- [ main] c.e.b.BasestationApplicationKt : The following profiles are active: dev
2018-01-06 13:43:03.637 INFO 9144 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#294e5088: startup date [Sat Jan 06 13:43:03 CET 2018]; root of context hierarchy
2018-01-06 13:43:05.578 INFO 9144 --- [ main] org.xnio : XNIO version 3.3.8.Final
2018-01-06 13:43:05.600 INFO 9144 --- [ main] org.xnio.nio : XNIO NIO Implementation Version 3.3.8.Final
2018-01-06 13:43:05.695 WARN 9144 --- [ main] io.undertow.websockets.jsr : UT026009: XNIO worker was not set on WebSocketDeploymentInfo, the default worker will be used
2018-01-06 13:43:05.695 WARN 9144 --- [ main] io.undertow.websockets.jsr : UT026010: Buffer pool was not set on WebSocketDeploymentInfo, the default pool will be used
2018-01-06 13:43:05.721 INFO 9144 --- [ main] io.undertow.servlet : Initializing Spring embedded WebApplicationContext
2018-01-06 13:43:05.722 INFO 9144 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 2088 ms
2018-01-06 13:43:05.851 INFO 9144 --- [ main] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2018-01-06 13:43:05.857 INFO 9144 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-01-06 13:43:07.323 INFO 9144 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public com.app.basestation.model.Message com.app.basestation.BasestationController.home()
2018-01-06 13:43:07.330 INFO 9144 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-01-06 13:43:07.349 INFO 9144 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-01-06 13:43:07.509 INFO 9144 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for #ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#294e5088: startup date [Sat Jan 06 13:43:03 CET 2018]; root of context hierarchy
2018-01-06 13:43:08.519 INFO 9144 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-01-06 13:43:08.553 INFO 9144 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 2147483647
2018-01-06 13:43:08.678 INFO 9144 --- [ main] o.s.b.w.e.u.UndertowServletWebServer : Undertow started on port(s) 11112 (http)
And the output from the PI:
2018-01-06 12:48:41.689 INFO 1 --- [ main] c.e.b.BasestationApplicationKt : Starting BasestationApplicationKt on ubuntu with PID 1 (/app.jar started by root in /)
2018-01-06 12:48:42.019 INFO 1 --- [ main] c.e.b.BasestationApplicationKt : The following profiles are active: prd
2018-01-06 12:48:49.827 INFO 1 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#128c152: startup date [Sat Jan 06 12:48:49 UTC 2018]; root of context hierarchy
2018-01-06 12:54:05.276 INFO 1 --- [ main] org.xnio : XNIO version 3.3.8.Final
2018-01-06 12:54:08.404 INFO 1 --- [ main] org.xnio.nio : XNIO NIO Implementation Version 3.3.8.Final
2018-01-06 12:54:15.847 WARN 1 --- [ main] io.undertow.websockets.jsr : UT026009: XNIO worker was not set on WebSocketDeploymentInfo, the default worker will be used
2018-01-06 12:54:15.852 WARN 1 --- [ main] io.undertow.websockets.jsr : UT026010: Buffer pool was not set on WebSocketDeploymentInfo, the default pool will be used
2018-01-06 12:54:19.930 INFO 1 --- [ main] io.undertow.servlet : Initializing Spring embedded WebApplicationContext
2018-01-06 12:54:19.934 INFO 1 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 330155 ms
2018-01-06 12:54:42.544 INFO 1 --- [ main] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2018-01-06 12:54:43.206 INFO 1 --- [ main] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-01-06 12:57:18.683 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/],methods=[GET]}" onto public com.app.basestation.model.Message com.app.basestation.BasestationController.home()
2018-01-06 12:57:19.734 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-01-06 12:57:19.758 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-01-06 12:57:44.597 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for #ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext#128c152: startup date [Sat Jan 06 12:48:49 UTC 2018]; root of context hierarchy
2018-01-06 12:59:36.677 INFO 1 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-01-06 12:59:37.807 INFO 1 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 2147483647
2018-01-06 12:59:42.664 INFO 1 --- [ main] o.s.b.w.e.u.UndertowServletWebServer : Undertow started on port(s) 11112 (http)

Answer 1

Update:
For those reading this, I moved back to OpenJDK in 2019 due to the new Oracle policies. What I noticed is that OpenJDK has made significant performance improvements recently. If you use OpenJDK 11 and above, it has similar performance to Oracle JDK and you can easily configure its language level to work with Java 8 code. That said, if this does not work for you, try the below.
I moved to a new image: Oracle JDK instead of OpenJDK as #snodnipper suggested.
There were several things I had to do including installing a more recent version of Java 8 than the one available in the standard repository. This is the Dockerfile that ended up working for me, and now the application starts in 2 minutes.
FROM resin/raspberrypi3-buildpack-deps:jessie-scm
ENV LANG C.UTF-8
ENV JAVA_HOME /usr/lib/jvm/java-8-oracle
RUN ["cross-build-start"]
RUN echo "deb http://archive.raspberrypi.org/debian/ jessie main ui staging" > /etc/apt/sources.list.d/raspi.list
RUN rm -f /usr/bin/entry.sh
RUN wget -qO - http://archive.raspberrypi.org/debian/raspberrypi.gpg.key | apt-key add -
RUN { \
echo '#!/bin/bash'; \
echo 'set -e'; \
echo; \
echo 'dirname "$(dirname "$(readlink -f "$(which javac || which java)")")"'; \
} > /usr/local/bin/docker-java-home && \
chmod +x /usr/local/bin/docker-java-home
RUN apt-key adv --recv-key --keyserver keyserver.ubuntu.com C2518248EEA14886 && \
echo "deb http://ppa.launchpad.net/webupd8team/java/ubuntu xenial main" >> /etc/apt/sources.list.d/raspi.list
RUN set -x && \
apt-get update && \
apt-cache madison oracle-java8-installer && \
echo debconf shared/accepted-oracle-license-v1-1 select true | debconf-set-selections && \
apt-get install -y oracle-java8-installer oracle-java8-set-default && \
rm -rf /var/lib/apt/lists/* && \
[ "$JAVA_HOME" = "$(docker-java-home)" ]
RUN [ "cross-build-end" ]
ADD build/libs/app-0.0.1-SNAPSHOT.jar /app.jar
ENV JAVA_OPTS=""
ENTRYPOINT exec java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar