Spring Boot Restful service with incremental memory without load - rest

Question

I have deployed Spring Boot Restful service [spring-boot-starter-parent -
1.3.0.RELEASE] along with: -
spring-boot-starter-cloud-connectors,
spring-boot-starter-data-rest,
spring-boot-starter-jdbc,
spring-boot-starter-test,
spring-boot-configuration-processor,
spring-context-support[4.1.2.RELEASE] and
spring-cloud-starter-parent[Brixton.M4]
maven dependencies. Also connected with MySQL and AutoScalar marketplace services.
This restful service is working excellent with respect to SLA and memory utilisation. However, I have observed following concerns:
The application has been deployed with initial memory however after
couple of minutes (say 15-20 minutes), it is keep growing by 2-5MBs
every couple-of-minutes. However there is no load (service call).
After a huge work load, the application get reached on certain memory (say 600MB). But the Memory is not coming down after the load
(even in idle state for a while ). However due to above point 1, the
memory is keep growing.
The JMX is showing that GC is calling both minor and major while work load and following is the Spring Metrics through spring-boot-starter-actuator:
{"_links" : {"self" : {"href" : "https://Promotion/metrics"}},"mem" :
376320,"mem.free" : 199048,"processors" : 4,"instance.uptime" :
6457682,"uptime" : 6464241,"systemload.average" : 0.05,"heap.committed"
: 376320,"heap.init" : 382976,"heap.used" : 177271,"heap" :
376320,"threads.peak" : 22,"threads.daemon" : 20,"threads.totalStarted"
: 27,"threads" : 22,"classes" : 9916,"classes.loaded" :
9916,"classes.unloaded" : 0,"gc.ps_scavenge.count" :
47,"gc.ps_scavenge.time" : 344,"gc.ps_marksweep.count" :
0,"gc.ps_marksweep.time" : 0,"httpsessions.max" :
-1,"httpsessions.active" : 0,"datasource.primary.active" :
0,"datasource.primary.usage" : 0.0,"gauge.response.metrics" :
7.0,"gauge.response.BuyMoreSaveMore.getDiscDetails" :
14.0,"counter.status.200.metrics" :
7,"counter.status.200.BuyMoreSaveMore.getDiscDetails" : 850}