spring boot app keep print stack and heap info to docker log file

we are using docker to deploy our spring boot app, when I use docker logs to view the log, I find out the app keep print stack and heap info every few seconds.

below is a snap of it, anybody help?

{"log":"   java.lang.Thread.State: WAITING (on object monitor)n","stream":"stdout","time":"2019-07-11T02:09:34.067958073Z"}
{"log":"u0009at java.lang.Object.wait(Native Method)n","stream":"stdout","time":"2019-07-11T02:09:34.067962201Z"}
{"log":"u0009at java.lang.Object.wait(Object.java:502)n","stream":"stdout","time":"2019-07-11T02:09:34.067967791Z"}
{"log":"u0009at java.lang.ref.Reference.tryHandlePending(Reference.java:191)n","stream":"stdout","time":"2019-07-11T02:09:34.067972029Z"}
{"log":"u0009- locked u003c0x0000000080017c10u003e (a java.lang.ref.Reference$Lock)n","stream":"stdout","time":"2019-07-11T02:09:34.067976408Z"}
{"log":"u0009at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)n","stream":"stdout","time":"2019-07-11T02:09:34.067984762Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.06798907Z"}
{"log":""VM Thread" os_prio=0 tid=0x00007f58f40fa800 nid=0xa runnable n","stream":"stdout","time":"2019-07-11T02:09:34.067993044Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.067997277Z"}
{"log":""GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007f58f401f000 nid=0x8 runnable n","stream":"stdout","time":"2019-07-11T02:09:34.068001186Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.068005634Z"}
{"log":""GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007f58f4020800 nid=0x9 runnable n","stream":"stdout","time":"2019-07-11T02:09:34.068010605Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.068014993Z"}
{"log":""VM Periodic Task Thread" os_prio=0 tid=0x00007f58f4146000 nid=0x11 waiting on condition n","stream":"stdout","time":"2019-07-11T02:09:34.068019023Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.068023241Z"}
{"log":"JNI global references: 3399n","stream":"stdout","time":"2019-07-11T02:09:34.068027334Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.068031201Z"}
{"log":"Heapn","stream":"stdout","time":"2019-07-11T02:09:34.068035227Z"}
{"log":" PSYoungGen      total 1578496K, used 1202825K [0x000000009e800000, 0x0000000100000000, 0x0000000100000000)n","stream":"stdout","time":"2019-07-11T02:09:34.068039232Z"}
{"log":"  eden space 1559552K, 76% used [0x000000009e800000,0x00000000e7401ac8,0x00000000fdb00000)n","stream":"stdout","time":"2019-07-11T02:09:34.068043579Z"}
{"log":"  from space 18944K, 57% used [0x00000000fdb00000,0x00000000fe5a0b20,0x00000000fed80000)n","stream":"stdout","time":"2019-07-11T02:09:34.068047905Z"}
{"log":"  to   space 18944K, 0% used [0x00000000fed80000,0x00000000fed80000,0x0000000100000000)n","stream":"stdout","time":"2019-07-11T02:09:34.068051966Z"}
{"log":" ParOldGen       total 499712K, used 130842K [0x0000000080000000, 0x000000009e800000, 0x000000009e800000)n","stream":"stdout","time":"2019-07-11T02:09:34.068056199Z"}
{"log":"  object space 499712K, 26% used [0x0000000080000000,0x0000000087fc68b0,0x000000009e800000)n","stream":"stdout","time":"2019-07-11T02:09:34.068060675Z"}
{"log":" Metaspace       used 117332K, capacity 128212K, committed 128280K, reserved 1161216Kn","stream":"stdout","time":"2019-07-11T02:09:34.068064843Z"}
{"log":"  class space    used 14583K, capacity 16649K, committed 16680K, reserved 1048576Kn","stream":"stdout","time":"2019-07-11T02:09:34.068069068Z"}
{"log":"n","stream":"stdout","time":"2019-07-11T02:09:34.068073268Z"}

docker version

Docker version 18.06.1-ce, build e68fc7a

java version

[email protected]:/# java -version
openjdk version "1.8.0_111"
OpenJDK Runtime Environment (build 1.8.0_111-8u111-b14-2~bpo8+1-b14)
OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode)

logback config

<configuration>
    <appender name="stdout" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.core.encoder.LayoutWrappingEncoder">
            <layout class="ch.qos.logback.contrib.json.classic.JsonLayout">
                <timestampFormat>yyyy-MM-dd'T'HH:mm:ss.SSSX</timestampFormat>
                <jsonFormatter class="ch.qos.logback.contrib.jackson.JacksonJsonFormatter"/>
                <appendLineSeparator>true</appendLineSeparator>
            </layout>
        </encoder>
    </appender>

    <root level="info">
        <appender-ref ref="stdout"/>
    </root>
</configuration>

Source: StackOverflow