Spring Boot application slow memory leak - spring-boot

Question

I recently deployed a Spring Boot application that is scheduled to run every day in order to parse new data from a Cassandra cluster. After around 20 hours of work (some million read/write accesses to Cassandra) some memory issues arise and at each iteration (the exception is caught within the loop) I have this error:
java.lang.RuntimeException: java.lang.IllegalStateException: java.lang.reflect.InvocationTargetException
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.createAccessorClass(ClassGeneratingPropertyAccessorFactory.java:170)
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.potentiallyCreateAndRegisterPersistentPropertyAccessorClass(ClassGeneratingPropertyAccessorFactory.java:154)
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.getPropertyAccessor(ClassGeneratingPropertyAccessorFactory.java:80)
at org.springframework.data.mapping.model.BasicPersistentEntity.getPropertyAccessor(BasicPersistentEntity.java:425)
at org.springframework.data.cassandra.convert.MappingCassandraConverter.getConvertingAccessor(MappingCassandraConverter.java:611)
at org.springframework.data.cassandra.convert.MappingCassandraConverter.readEntityFromRow(MappingCassandraConverter.java:172)
at org.springframework.data.cassandra.convert.MappingCassandraConverter.readRow(MappingCassandraConverter.java:149)
at com.myapp.utils.CassandraIterable$1.next(CassandraIterable.java:35)
at com.myapp.service.packer.PositionParsingService.parse(PositionParsingService.java:60)
at com.myapp.service.packer.PositionLoadService.update(PositionLoadService.java:202)
at com.myapp.service.packer.PositionLoadService.updateVehicle(PositionLoadService.java:129)
at com.myapp.service.packer.PositionLoadService.updateAllVehicles(PositionLoadService.java:99)
at com.myapp.service.packer.PositionLoadService.updateAllVehicles(PositionLoadService.java:84)
at com.myapp.service.packer.PositionLoadService$$FastClassBySpringCGLIB$$2605bc6c.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:721)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.aop.interceptor.AsyncExecutionInterceptor$1.call(AsyncExecutionInterceptor.java:115)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: java.lang.reflect.InvocationTargetException
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$Evil.defineClass(ClassGeneratingPropertyAccessorFactory.java:1480)
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$PropertyAccessorClassGenerator.generateCustomAccessorClass(ClassGeneratingPropertyAccessorFactory.java:282)
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory.createAccessorClass(ClassGeneratingPropertyAccessorFactory.java:168)
... 21 common frames omitted
Caused by: java.lang.reflect.InvocationTargetException: null
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.data.mapping.model.ClassGeneratingPropertyAccessorFactory$Evil.defineClass(ClassGeneratingPropertyAccessorFactory.java:1476)
... 23 common frames omitted
Caused by: java.lang.OutOfMemoryError: Compressed class space
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
... 28 common frames omitted
By analysing the memory dumps produced after the issue occurred I had this report:
From Java mission control, after I run a garbage collection, I get:
I don't think my code is directly responsible for the leak, even though there could be something it isn't releasing when it should or there could be some config issue I overlooked.
I tried to upgrade java from JDK SE 8u60 to 8u121 and to upgrade Spring boot to version 1.5.2.RELEASE. Here's the complete list of dependencies:
com.myapp:jar:0.0.1-SNAPSHOT
+- org.springframework.boot:spring-boot-starter-data-jpa:jar:1.5.2.RELEASE:compile
| +- org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile
| | +- (org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| | +- org.springframework.boot:spring-boot-starter-logging:jar:1.5.2.RELEASE:compile
| | | +- ch.qos.logback:logback-classic:jar:1.1.11:compile
| | | | +- ch.qos.logback:logback-core:jar:1.1.11:compile
| | | | \- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.22; omitted for duplicate)
| | | +- org.slf4j:jcl-over-slf4j:jar:1.7.24:compile
| | | | \- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.22; omitted for duplicate)
| | | +- org.slf4j:jul-to-slf4j:jar:1.7.24:compile
| | | | \- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.22; omitted for duplicate)
| | | \- org.slf4j:log4j-over-slf4j:jar:1.7.24:compile
| | | \- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.22; omitted for duplicate)
| | +- org.springframework:spring-core:jar:4.3.7.RELEASE:compile
| | \- org.yaml:snakeyaml:jar:1.17:runtime
| +- org.springframework.boot:spring-boot-starter-aop:jar:1.5.2.RELEASE:compile
| | +- (org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| | +- org.springframework:spring-aop:jar:4.3.7.RELEASE:compile
| | | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | \- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | \- org.aspectj:aspectjweaver:jar:1.8.9:compile
| +- org.springframework.boot:spring-boot-starter-jdbc:jar:1.5.2.RELEASE:compile
| | +- (org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| | +- org.apache.tomcat:tomcat-jdbc:jar:8.5.11:compile
| | | \- org.apache.tomcat:tomcat-juli:jar:8.5.11:compile
| | \- org.springframework:spring-jdbc:jar:4.3.7.RELEASE:compile
| | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | \- (org.springframework:spring-tx:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- org.hibernate:hibernate-core:jar:5.0.12.Final:compile
| | +- org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile
| | +- org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile
| | +- org.javassist:javassist:jar:3.21.0-GA:compile (version managed from 3.18.1-GA)
| | +- antlr:antlr:jar:2.7.7:compile
| | +- org.jboss:jandex:jar:2.0.0.Final:compile
| | +- dom4j:dom4j:jar:1.6.1:compile
| | \- org.hibernate.common:hibernate-commons-annotations:jar:5.0.1.Final:compile
| | \- (org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile - omitted for duplicate)
| +- org.hibernate:hibernate-entitymanager:jar:5.0.12.Final:compile
| | +- (org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile - omitted for duplicate)
| | +- (org.hibernate:hibernate-core:jar:5.0.12.Final:compile - omitted for duplicate)
| | +- (dom4j:dom4j:jar:1.6.1:compile - omitted for duplicate)
| | +- (org.hibernate.common:hibernate-commons-annotations:jar:5.0.1.Final:compile - omitted for duplicate)
| | +- (org.hibernate.javax.persistence:hibernate-jpa-2.1-api:jar:1.0.0.Final:compile - omitted for duplicate)
| | \- (org.javassist:javassist:jar:3.21.0-GA:compile - version managed from 3.18.1-GA; omitted for duplicate)
| +- javax.transaction:javax.transaction-api:jar:1.2:compile
| +- org.springframework.data:spring-data-jpa:jar:1.11.1.RELEASE:compile
| | +- org.springframework.data:spring-data-commons:jar:1.13.1.RELEASE:compile
| | | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.22; omitted for duplicate)
| | | \- (org.slf4j:jcl-over-slf4j:jar:1.7.24:runtime - omitted for duplicate)
| | +- org.springframework:spring-orm:jar:4.3.7.RELEASE:compile
| | | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.springframework:spring-jdbc:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | \- (org.springframework:spring-tx:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- org.springframework:spring-context:jar:4.3.7.RELEASE:compile
| | | +- (org.springframework:spring-aop:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | | \- (org.springframework:spring-expression:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-aop:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-tx:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- org.springframework:spring-beans:jar:4.3.7.RELEASE:compile
| | | \- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- org.slf4j:slf4j-api:jar:1.7.24:compile
| | \- (org.slf4j:jcl-over-slf4j:jar:1.7.24:compile - scope updated from runtime; omitted for duplicate)
| \- org.springframework:spring-aspects:jar:4.3.7.RELEASE:compile
| \- (org.aspectj:aspectjweaver:jar:1.8.9:compile - omitted for duplicate)
+- org.springframework.boot:spring-boot-starter-web:jar:1.5.2.RELEASE:compile
| +- (org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| +- org.springframework.boot:spring-boot-starter-tomcat:jar:1.5.2.RELEASE:compile
| | +- org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.11:compile
| | +- org.apache.tomcat.embed:tomcat-embed-el:jar:8.5.11:compile
| | \- org.apache.tomcat.embed:tomcat-embed-websocket:jar:8.5.11:compile
| | \- (org.apache.tomcat.embed:tomcat-embed-core:jar:8.5.11:compile - omitted for duplicate)
| +- org.hibernate:hibernate-validator:jar:5.3.4.Final:compile
| | +- javax.validation:validation-api:jar:1.1.0.Final:compile
| | +- (org.jboss.logging:jboss-logging:jar:3.3.0.Final:compile - omitted for duplicate)
| | \- com.fasterxml:classmate:jar:1.3.3:compile (version managed from 1.3.1)
| +- com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile
| | +- (com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile - omitted for duplicate)
| | \- (com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile - omitted for duplicate)
| +- org.springframework:spring-web:jar:4.3.7.RELEASE:compile
| | +- (org.springframework:spring-aop:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-context:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | \- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| \- org.springframework:spring-webmvc:jar:4.3.7.RELEASE:compile
| +- (org.springframework:spring-aop:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- (org.springframework:spring-context:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- org.springframework:spring-expression:jar:4.3.7.RELEASE:compile
| | \- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| \- (org.springframework:spring-web:jar:4.3.7.RELEASE:compile - omitted for duplicate)
+- org.springframework.boot:spring-boot-starter-data-cassandra:jar:1.5.2.RELEASE:compile
| +- (org.springframework.boot:spring-boot-starter:jar:1.5.2.RELEASE:compile - omitted for duplicate)
| +- org.springframework:spring-tx:jar:4.3.7.RELEASE:compile
| | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | \- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| \- org.springframework.data:spring-data-cassandra:jar:1.5.1.RELEASE:compile
| +- org.springframework.data:spring-cql:jar:1.5.1.RELEASE:compile
| | +- (org.springframework:spring-context:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-beans:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-expression:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework:spring-tx:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | +- (org.springframework.data:spring-data-commons:jar:1.13.1.RELEASE:compile - omitted for duplicate)
| | +- (com.datastax.cassandra:cassandra-driver-core:jar:3.1.4:compile - version managed from 3.1.3; omitted for duplicate)
| | +- (com.google.guava:guava:jar:19.0:compile - omitted for conflict with 16.0.1)
| | +- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.7; omitted for duplicate)
| | \- (org.slf4j:jcl-over-slf4j:jar:1.7.24:runtime - omitted for duplicate)
| +- (org.springframework:spring-expression:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| +- (org.springframework.data:spring-data-commons:jar:1.13.1.RELEASE:compile - omitted for duplicate)
| +- (com.datastax.cassandra:cassandra-driver-core:jar:3.1.4:compile - version managed from 3.1.3; omitted for duplicate)
| +- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.7; omitted for duplicate)
| \- (org.slf4j:jcl-over-slf4j:jar:1.7.24:compile - scope updated from runtime; omitted for duplicate)
+- org.springframework.boot:spring-boot-devtools:jar:1.5.2.RELEASE:compile
| +- org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile
| | +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| | \- (org.springframework:spring-context:jar:4.3.7.RELEASE:compile - omitted for duplicate)
| \- org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.RELEASE:compile
| \- (org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:compile - omitted for duplicate)
+- com.datastax.cassandra:cassandra-driver-mapping:jar:3.1.4:compile
| \- com.datastax.cassandra:cassandra-driver-core:jar:3.1.4:compile
| +- io.netty:netty-handler:jar:4.0.37.Final:compile
| | +- io.netty:netty-buffer:jar:4.0.37.Final:compile
| | | \- io.netty:netty-common:jar:4.0.37.Final:compile
| | +- io.netty:netty-transport:jar:4.0.37.Final:compile
| | | \- (io.netty:netty-buffer:jar:4.0.37.Final:compile - omitted for duplicate)
| | \- io.netty:netty-codec:jar:4.0.37.Final:compile
| | \- (io.netty:netty-transport:jar:4.0.37.Final:compile - omitted for duplicate)
| +- com.google.guava:guava:jar:16.0.1:compile
| +- io.dropwizard.metrics:metrics-core:jar:3.1.3:compile (version managed from 3.1.2)
| | \- (org.slf4j:slf4j-api:jar:1.7.24:compile - version managed from 1.7.7; omitted for duplicate)
| +- com.github.jnr:jnr-ffi:jar:2.0.7:compile
| | +- com.github.jnr:jffi:jar:1.2.10:compile
| | +- com.github.jnr:jffi:jar:native:1.2.10:runtime
| | +- org.ow2.asm:asm:jar:5.0.3:compile
| | +- org.ow2.asm:asm-commons:jar:5.0.3:compile
| | | \- (org.ow2.asm:asm-tree:jar:5.0.3:compile - omitted for duplicate)
| | +- org.ow2.asm:asm-analysis:jar:5.0.3:compile
| | | \- (org.ow2.asm:asm-tree:jar:5.0.3:compile - omitted for duplicate)
| | +- org.ow2.asm:asm-tree:jar:5.0.3:compile
| | | \- (org.ow2.asm:asm:jar:5.0.3:compile - omitted for duplicate)
| | +- org.ow2.asm:asm-util:jar:5.0.3:compile
| | | \- (org.ow2.asm:asm-tree:jar:5.0.3:compile - omitted for duplicate)
| | \- com.github.jnr:jnr-x86asm:jar:1.0.2:compile
| \- com.github.jnr:jnr-posix:jar:3.0.27:compile
| +- (com.github.jnr:jnr-ffi:jar:2.0.7:compile - omitted for duplicate)
| \- com.github.jnr:jnr-constants:jar:0.9.0:compile
+- com.fasterxml.jackson.datatype:jackson-datatype-jsr310:jar:2.8.7:compile
| +- com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile
| +- com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile
| \- (com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile - omitted for duplicate)
+- com.oracle.jdbc:ojdbc7:jar:12.1.0.2:compile
| +- com.oracle.jdbc:xdb6:jar:12.1.0.2:compile
| +- com.oracle.jdbc:orai18n:jar:12.1.0.2:compile
| +- com.oracle.jdbc:xmlparserv2:jar:12.1.0.2:compile
| +- com.oracle.jdbc:oraclepki:jar:12.1.0.2:compile
| +- com.oracle.jdbc:osdt_cert:jar:12.1.0.2:compile
| \- com.oracle.jdbc:osdt_core:jar:12.1.0.2:compile
+- com.mycompany:Pandora-json:jar:2.1.0-SNAPSHOT:compile
| +- (com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile - version managed from 2.5.4; omitted for duplicate)
| +- (com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile - version managed from 2.5.4; omitted for duplicate)
| +- com.fasterxml.jackson.datatype:jackson-datatype-joda:jar:2.8.7:compile (version managed from 2.5.4)
| | +- (com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile - version managed from 2.5.4; omitted for duplicate)
| | +- (com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile - omitted for duplicate)
| | +- (com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile - version managed from 2.5.4; omitted for duplicate)
| | \- (joda-time:joda-time:jar:2.9.7:compile - version managed from 2.7; omitted for duplicate)
| \- com.fasterxml.jackson.datatype:jackson-datatype-guava:jar:2.8.7:compile (version managed from 2.4.0)
| +- (com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile - version managed from 2.5.4; omitted for duplicate)
| +- (com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile - omitted for duplicate)
| \- (com.google.guava:guava:jar:16.0:compile - omitted for conflict with 16.0.1)
+- javax.inject:javax.inject:jar:1:compile
+- joda-time:joda-time:jar:2.9.7:compile
+- org.projectlombok:lombok:jar:1.16.14:compile
+- org.springframework.boot:spring-boot-starter-test:jar:1.5.2.RELEASE:test
| +- org.springframework.boot:spring-boot-test:jar:1.5.2.RELEASE:test
| | \- (org.springframework.boot:spring-boot:jar:1.5.2.RELEASE:test - omitted for duplicate)
| +- org.springframework.boot:spring-boot-test-autoconfigure:jar:1.5.2.RELEASE:test
| | +- (org.springframework.boot:spring-boot-test:jar:1.5.2.RELEASE:test - omitted for duplicate)
| | \- (org.springframework.boot:spring-boot-autoconfigure:jar:1.5.2.RELEASE:test - omitted for duplicate)
| +- com.jayway.jsonpath:json-path:jar:2.2.0:test
| | +- net.minidev:json-smart:jar:2.2.1:test
| | | \- net.minidev:accessors-smart:jar:1.1:test
| | | \- (org.ow2.asm:asm:jar:5.0.3:test - omitted for duplicate)
| | \- (org.slf4j:slf4j-api:jar:1.7.24:test - version managed from 1.7.16; omitted for duplicate)
| +- junit:junit:jar:4.12:test
| | \- (org.hamcrest:hamcrest-core:jar:1.3:test - version managed from 1.1; omitted for duplicate)
| +- (org.assertj:assertj-core:jar:2.6.0:test - omitted for conflict with 3.6.2)
| +- org.mockito:mockito-core:jar:1.10.19:test
| | +- (org.hamcrest:hamcrest-core:jar:1.3:test - version managed from 1.1; omitted for duplicate)
| | \- org.objenesis:objenesis:jar:2.1:test
| +- org.hamcrest:hamcrest-core:jar:1.3:test
| +- org.hamcrest:hamcrest-library:jar:1.3:test
| | \- (org.hamcrest:hamcrest-core:jar:1.3:test - version managed from 1.1; omitted for duplicate)
| +- org.skyscreamer:jsonassert:jar:1.4.0:test
| | \- com.vaadin.external.google:android-json:jar:0.0.20131108.vaadin1:test
| +- (org.springframework:spring-core:jar:4.3.7.RELEASE:compile - scope updated from test; omitted for duplicate)
| \- org.springframework:spring-test:jar:4.3.7.RELEASE:test
| \- (org.springframework:spring-core:jar:4.3.7.RELEASE:test - omitted for duplicate)
+- commons-lang:commons-lang:jar:2.2:compile
+- org.assertj:assertj-core:jar:3.6.2:compile
+- org.mockito:mockito-all:jar:1.10.19:test
+- net.sourceforge.dynamicreports:dynamicreports-core:jar:4.1.1:compile
| +- net.sf.jasperreports:jasperreports:jar:6.2.2:compile
| | +- commons-beanutils:commons-beanutils:jar:1.9.3:compile (version managed from 1.9.0)
| | | \- (commons-collections:commons-collections:jar:3.2.2:compile - omitted for duplicate)
| | +- commons-collections:commons-collections:jar:3.2.2:compile
| | +- commons-digester:commons-digester:jar:2.1:compile
| | | \- (commons-beanutils:commons-beanutils:jar:1.9.3:compile - version managed from 1.8.3; omitted for duplicate)
| | +- commons-logging:commons-logging:jar:1.1.1:compile
| | +- com.lowagie:itext:jar:2.1.7.js5:compile
| | | \- bouncycastle:bcprov-jdk14:jar:138:compile
| | +- org.jfree:jcommon:jar:1.0.23:compile
| | +- org.jfree:jfreechart:jar:1.0.19:compile
| | | \- (org.jfree:jcommon:jar:1.0.23:compile - omitted for duplicate)
| | +- org.eclipse.jdt.core.compiler:ecj:jar:4.3.1:compile
| | +- (com.fasterxml.jackson.core:jackson-core:jar:2.8.7:compile - version managed from 2.1.4; omitted for duplicate)
| | +- (com.fasterxml.jackson.core:jackson-databind:jar:2.8.7:compile - version managed from 2.1.4; omitted for duplicate)
| | +- (com.fasterxml.jackson.core:jackson-annotations:jar:2.8.0:compile - version managed from 2.1.4; omitted for duplicate)
| | \- com.google.zxing:core:jar:2.3.0:compile
| +- org.apache.commons:commons-lang3:jar:3.1:compile
| +- net.sf.barcode4j:barcode4j:jar:2.0:compile
| | +- avalon-framework:avalon-framework-impl:jar:4.2.0:compile
| | \- xml-apis:xml-apis:jar:1.4.01:compile (version managed from 1.3.04)
| \- org.apache.xmlgraphics:batik-bridge:jar:1.8:compile
| +- org.apache.xmlgraphics:batik-anim:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-awt-util:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-css:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-dom:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-ext:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-parser:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-svg-dom:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | +- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| | \- (xml-apis:xml-apis-ext:jar:1.3.04:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-awt-util:jar:1.8:compile
| | \- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-css:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-ext:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | +- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| | \- (xml-apis:xml-apis-ext:jar:1.3.04:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-dom:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-css:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-ext:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-xml:jar:1.8:compile - omitted for duplicate)
| | +- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| | \- (xml-apis:xml-apis-ext:jar:1.3.04:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-ext:jar:1.8:compile
| | \- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| +- org.apache.xmlgraphics:batik-gvt:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-awt-util:jar:1.8:compile - omitted for duplicate)
| | \- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-parser:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-awt-util:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-xml:jar:1.8:compile - omitted for duplicate)
| | \- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| +- org.apache.xmlgraphics:batik-script:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-anim:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | \- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| +- org.apache.xmlgraphics:batik-svg-dom:jar:1.8:compile
| | +- (org.apache.xmlgraphics:batik-awt-util:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-css:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-dom:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-ext:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-parser:jar:1.8:compile - omitted for duplicate)
| | +- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| | +- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| | \- (xml-apis:xml-apis-ext:jar:1.3.04:compile - omitted for duplicate)
| +- org.apache.xmlgraphics:batik-util:jar:1.8:compile
| +- org.apache.xmlgraphics:batik-xml:jar:1.8:compile
| | \- (org.apache.xmlgraphics:batik-util:jar:1.8:compile - omitted for duplicate)
| +- (xml-apis:xml-apis:jar:1.4.01:compile - version managed from 1.3.04; omitted for duplicate)
| \- xml-apis:xml-apis-ext:jar:1.3.04:compile
+- org.apache.poi:poi:jar:3.14:compile
| \- commons-codec:commons-codec:jar:1.10:compile
\- org.apache.poi:poi-ooxml:jar:3.14:compile
+- (org.apache.poi:poi:jar:3.14:compile - omitted for duplicate)
+- org.apache.poi:poi-ooxml-schemas:jar:3.14:compile
| \- org.apache.xmlbeans:xmlbeans:jar:2.6.0:compile
| \- stax:stax-api:jar:1.0.1:compile
\- com.github.virtuald:curvesapi:jar:1.03:compile

Answer 1

I finally managed to fix the issue. What was causing it was the fact that I was re-instantiating MappingCassandraConverter for each instance of CassandraIterable.
public class CassandraIterable<T> implements Iterable<T> {
private final Iterator<Row> iterator;
private final Class<T> entityType;
private final MappingCassandraConverter converter = new MappingCassandraConverter ();
...
}
while I should have created it once and passed it to the Iterable:
public class CassandraIterable<T> implements Iterable<T> {
private final Iterator<Row> iterator;
private final Class<T> entityType;
private final MappingCassandraConverter converter;
public CassandraIterable(Iterator<Row> iterator, Class<T> entityType, MappingCassandraConverter converter) {
this.iterator = iterator;
this.entityType = entityType;
this.converter = converter;
}
#Override
public Iterator<T> iterator() {
return
new Iterator<T>() {
#Override
public boolean hasNext() {
return
iterator.hasNext();
}
#Override
public T next() {
return
converter.readRow(entityType, iterator.next());
}
};
}
}
MappingCassandraConverter wasn't garbage collected (I presume that the Cassandra session was pointing to it) and the accessor to my class was probably pointed by the the converter.
The reason why I couldn't find the leak is that there wasn't a specific Type involved in the leak:
I was expecting to see one of my types repeated million of times in memory because of the leak instead. The reason why this wasn't happening is the fact that the issue in my code was creating a lot of accessors to Cassandra entities even though there was just one class type to be generated. For this reason the classes that were involved in the leak were something like:
and they were not at the top of the list that was grouped by type sorted by the total size.