Develop Reference

Java Native Memory 'Other' section consumes a lot of memory

Prerequisites
Application is run in docker-container with Java openjdk version "13.0.1" with these options:
-Xmx6G -XX:MaxHeapFreeRatio=30 -XX:MinHeapFreeRatio=10 -XX:+AlwaysActAsServerClassMachine -XX:+UseContainerSupport -XX:+HeapDumpOnOutOfMemoryError -XX:+ExitOnOutOfMemoryError -XX:HeapDumpPath==/.../crush.hprof -XX:+UnlockDiagnosticVMOptions -XX:NativeMemoryTracking=summary -XX:+PrintNMTStatistics -Xlog:gc*:file=/var/log/.../log.gc.log:time::filecount=5,filesize=100000
When I run jcmd 1 VM.native_memory, I get this:
Total: reserved=9081562KB, committed=1900002KB
- Java Heap (reserved=6291456KB, committed=896000KB)
(mmap: reserved=6291456KB, committed=896000KB)
- Class (reserved=1221794KB, committed=197034KB)
(classes #34434)
( instance classes #32536, array classes #1898)
(malloc=7330KB #121979)
(mmap: reserved=1214464KB, committed=189704KB)
( Metadata: )
( reserved=165888KB, committed=165752KB)
( used=161911KB)
( free=3841KB)
( waste=0KB =0.00%)
( Class space:)
( reserved=1048576KB, committed=23952KB)
( used=21501KB)
( free=2451KB)
( waste=0KB =0.00%)
- Thread (reserved=456661KB, committed=50141KB)
(thread #442)
(stack: reserved=454236KB, committed=47716KB)
(malloc=1572KB #2654)
(arena=853KB #882)
- Code (reserved=255027KB, committed=100419KB)
(malloc=7343KB #26005)
(mmap: reserved=247684KB, committed=93076KB)
- GC (reserved=316675KB, committed=116459KB)
(malloc=47311KB #70516)
(mmap: reserved=269364KB, committed=69148KB)
- Compiler (reserved=1429KB, committed=1429KB)
(malloc=1634KB #2498)
(arena=18014398509481779KB #5)
- Internal (reserved=2998KB, committed=2998KB)
(malloc=2962KB #5480)
(mmap: reserved=36KB, committed=36KB)
- Other (reserved=446581KB, committed=446581KB)
(malloc=446581KB #368)
- Symbol (reserved=36418KB, committed=36418KB)
(malloc=34460KB #906917)
(arena=1958KB #1)
- Native Memory Tracking (reserved=18786KB, committed=18786KB)
(malloc=587KB #8291)
(tracking overhead=18199KB)
- Shared class space (reserved=11180KB, committed=11180KB)
(mmap: reserved=11180KB, committed=11180KB)
- Arena Chunk (reserved=19480KB, committed=19480KB)
(malloc=19480KB)
- Logging (reserved=7KB, committed=7KB)
(malloc=7KB #271)
- Arguments (reserved=17KB, committed=17KB)
(malloc=17KB #471)
- Module (reserved=1909KB, committed=1909KB)
(malloc=1909KB #11057)
- Safepoint (reserved=8KB, committed=8KB)
(mmap: reserved=8KB, committed=8KB)
- Synchronization (reserved=1136KB, committed=1136KB)
(malloc=1136KB #6628)
Here we can see that 'Other' section consumes 446581 KB whereas total committed memory is 1900002 KB.
So, 'Other' section takes 23% of all committed memory!
Also this memory is not freed when application is running.
Because of this I changed java flag -XX:NativeMemoryTracking=summary to -XX:NativeMemoryTracking=detail to check where memory is allocated and got this 2 strange blocks of memory:
[0x00007f8db4b32bae] Unsafe_AllocateMemory0+0x8e
[0x00007f8da416e7db]
(malloc=298470KB type=Other #286)
[0x00007f8db4b32bae] Unsafe_AllocateMemory0+0x8e
[0x00007f8d9b84bc90]
(malloc=148111KB type=Other #82)
Analyze
I tried to use async-profiler to check event Unsafe_AllocateMemory0.
I run async-profiler as agent like this:
java -agentpath:/async-profiler/build/libasyncProfiler.so=start,event=itimer,Unsafe_AllocateMemory0,file=/var/log/.../unsafe_allocate_memory.html
And got this flamegraph: https://i.stack.imgur.com/PbE5D.png
Also, I tried to profile events malloc,mmap,mprotect. malloc showed the same flamegraph as event Unsafe_AllocateMemory0, but flamegraphs for mmap and mprotect were empty.
I thought that problem can be related with C2 compiler and disabled it, but after restart nothing changed - the 'Other' section still occupied a lot of memory memory. Moreover, this application is long-living and I'm not sure that disabling C2 can be a good idea.
I tried to use jeprof to check which part of code executes os.malloc
I run java application like this:
LD_PRELOAD=/usr/local/lib/libjemalloc.so MALLOC_CONF=prof:true,lg_prof_interval:30,lg_prof_sample:17 exec java -jar /srv/app/myapp.jar
After 10+ minutes I used jeprof and got this: https://i.stack.imgur.com/45adD.gif
And again there are 2 blocks of memory which occupied many native memory.
Result
I cannot find the place, which allocates so much memory.
Maybe someone can recommend how to spot the root cause of this problem? And what steps do I need to take to avoid this problem?
UPDATE 1
Thanks to apangin I have finally found the place, where so much memory is occupied!
It's related to Redisson/Lettuce, which are using Netty under the hood: flamegraph
I used experimental native mode and run java:
java -agentpath:/async-profiler/build/libasyncProfiler.so=start,event=nativemem,file=/var/log/.../profile.jfr -jar /srv/app/myapp.jar

Your async-profilers arguments seem wrong.
Change event=itimer,Unsafe_AllocateMemory0 to event=Unsafe_AllocateMemory0
async-profiler also has an experimental nativemem mode specifically for finding native memory leaks. See https://github.com/jvm-profiling-tools/async-profiler/discussions/491 for the details.
Other section in NMT typically includes off-heap memory allocated with Unsafe.allocateMemory, in particular, Direct ByteBuffers.

How does a JVM process allocate its memory?

I have a little gap in understanding how a JVM process allocates its own memory. As far as I know
RSS = Heap size + MetaSpace + OffHeap size
where OffHeap consists of thread stacks, direct buffers, mapped files (libraries and jars) and JVM code itself;
At the moment I’m trying to analyze my Java application (Spring Boot + Infinispan) which RSS is 779M (it runs in a docker container, so pid 1 is ok):
[ root#daf5a5ae9bb7:/data ]$ ps -o rss,vsz,sz 1
RSS VSZ SZ
798324 6242160 1560540
According to jvisualvm, committed Heap size is 374M
Metasapce size is 89M
In other words, I want to explain 799M - (374M + 89M) = 316M of OffHeap memory.
My app has (in average) 36 live threads.
Each of these threads consumes 1M:
[ root#fac6d0dfbbb4:/data ]$ java -XX:+PrintFlagsFinal -version |grep ThreadStackSize
intx CompilerThreadStackSize = 0
intx ThreadStackSize = 1024
intx VMThreadStackSize = 1024
So, here we can add 36M.
The only place where the app uses DirectBuffer is NIO. As far as I can see from JMX, it doesn’t consume a lot of resources - only 98K
The last step is mapped libs and jars. But according to pmap (full output)
[ root#daf5a5ae9bb7:/data ]$ pmap -x 1 | grep ".so.*" | awk '{ sum+=$3} END {print sum}'
12896K
plus
root#daf5a5ae9bb7:/data ]$ pmap -x 1 | grep “.jar" | awk '{ sum+=$3} END {print sum}'
9720K
we only have 20M here.
Hence, we still have to explain 316M - (36M + 20M) = 260M :(
Does anyone have any idea what I missed?

Approach:
You may want to use Java HotSpot Native Memory Tracking (NMT).
This may give you an exact list of memory allocated by the JVM, splitted up into the different areas heap, classes, threads, code, GC, compiler, internal, symbols, memory tracking, pooled free chunks, and unknown.
Usage:
You can start your application with -XX:NativeMemoryTracking=summary.
Observations of the current heap can be done with jcmd <pid> VM.native_memory summary.
Where to find jcmd / pid:
On a default OpedJDK installation on Ubuntu this can be found at /usr/bin/jcmd.
By just running jcmd without any parameter, you get a list of running Java applications.
user#pc:~$ /usr/bin/jcmd
5169 Main <-- 5169 is the pid
Output:
You will then receive a complete overview over your heap, looking something like the following:
Total: reserved=664192KB, committed=253120KB <--- total memory tracked by Native Memory Tracking
Java Heap (reserved=516096KB, committed=204800KB) <--- Java Heap
(mmap: reserved=516096KB, committed=204800KB)
Class (reserved=6568KB, committed=4140KB) <--- class metadata
(classes #665) <--- number of loaded classes
(malloc=424KB, #1000) <--- malloc'd memory, #number of malloc
(mmap: reserved=6144KB, committed=3716KB)
Thread (reserved=6868KB, committed=6868KB)
(thread #15) <--- number of threads
(stack: reserved=6780KB, committed=6780KB) <--- memory used by thread stacks
(malloc=27KB, #66)
(arena=61KB, #30) <--- resource and handle areas
Code (reserved=102414KB, committed=6314KB)
(malloc=2574KB, #74316)
(mmap: reserved=99840KB, committed=3740KB)
GC (reserved=26154KB, committed=24938KB)
(malloc=486KB, #110)
(mmap: reserved=25668KB, committed=24452KB)
Compiler (reserved=106KB, committed=106KB)
(malloc=7KB, #90)
(arena=99KB, #3)
Internal (reserved=586KB, committed=554KB)
(malloc=554KB, #1677)
(mmap: reserved=32KB, committed=0KB)
Symbol (reserved=906KB, committed=906KB)
(malloc=514KB, #2736)
(arena=392KB, #1)
Memory Tracking (reserved=3184KB, committed=3184KB)
(malloc=3184KB, #300)
Pooled Free Chunks (reserved=1276KB, committed=1276KB)
(malloc=1276KB)
Unknown (reserved=33KB, committed=33KB)
(arena=33KB, #1)
This gives a detailed overview of the different memory areas used by the JVM, and also shows the reserved and commited memory.
I don't know of a technique that gives you a more detailed memory consumption list.
Further reading:
You can also use -XX:NativeMemoryTracking=detail in combination with further jcmd commands. A more detailed explaination can be found at Java Platform, Standard Edition Troubleshooting Guide - 2.6 The jcmd Utility. You can check possible commands via "jcmd <pid> help"

Java OutOfMemory Error

I am seeing an OutOfMemory problem and I am not sure it is the PERM GEN area or the heap space. The error message does not say anything about which area ran out of memory.
Here is a partial stack trace:
The following is information that may be useful to the developer of BETWEENNESS: java.lang.OutOfMemoryError at java.util.zip.ZipFile.open(Native Method) at java.util.zip.ZipFile.(ZipFile.java:127) at java.util.zip.ZipFile.(ZipFile.java:143) at com..util.internal.ZipFiles.unzip(ZipFiles.java:91)
I looked at the heap space just before it ran out of memory using the jmap -heap command:
using thread-local object allocation.
Parallel GC with 23 thread(s)
Heap Configuration:
MinHeapFreeRatio = 40
MaxHeapFreeRatio = 70
MaxHeapSize = 31675383808 (30208.0MB)
NewSize = 1310720 (1.25MB)
MaxNewSize = 17592186044415 MB
OldSize = 5439488 (5.1875MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 21757952 (20.75MB)
MaxPermSize = 536870912 (512.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 9762177024 (9309.9375MB)
used = 7286558512 (6949.003707885742MB)
free = 2475618512 (2360.933792114258MB)
74.64071276403028% used
From Space:
capacity = 396230656 (377.875MB)
used = 340623360 (324.84375MB)
free = 55607296 (53.03125MB)
85.96592788620576% used
To Space:
capacity = 398131200 (379.6875MB)
used = 0 (0.0MB)
free = 398131200 (379.6875MB)
0.0% used
PS Old Generation
capacity = 1992163328 (1899.875MB)
used = 1455304512 (1387.8865356445312MB)
free = 536858816 (511.98846435546875MB)
73.05146578825087% used
PS Perm Generation
capacity = 418578432 (399.1875MB)
used = 418567008 (399.1766052246094MB)
free = 11424 (0.010894775390625MB)
99.99727076238844% used }
And also, I had supplied the following arguments to the JVM: -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/tmp/ but I do not see any heap.
My questions is why is the heap not being generated and how do I figure out which part of the JVm is getting full.
Thanks.

Your provided information says, that your PermGen is 99% full. And your Heap is already 73% full. So increasing both would not be bad at all.
Further you could activate the garbage collector's logging with -XX:+PrintGCDetails to get detailed information on how your JVM is using memory. Additionally activate -XX:+PrintGCTimeStamps and -XX:+PrintGCDateStamps. -Xloggc:$filename sends the logs to a file, which you could easily analyze with something like IMB PMAT tool or GCViewer.
Additionally you should consider using VisualVM to monitor your application while running.
Besides:
A colleague of mine found a smart way to get a heapdump many times faster through gdb:
cat > /tmp/dodump <<EOF
gcore jvm.core
detach
quit
EOF
time gdb --batch --command=/tmp/dodump --pid=`pgrep java`
jmap -dump:format=b,file=jvm.hprof `which java` jvm.core
rm jvm.core
gzip -9 jvm.hprof
Source
Credits go fully to him.

According to stack trace, OutOfMemoryError happens inside ZipFile.open() native method. This means that the problem has nothing to do with Java Heap size nor with PermGen. It is likely related with ZIP cache which is malloc'ed or mmap'ed internally by JDK library.
Try adding -Dsun.zip.disableMemoryMapping=true JVM option to see if it helps.
How large is ZIP file being opened?

Finding root cause of java.lang.OutOfMemoryError: Java heap space using Eclipse MAT

I am trying to find out which method/loop has given java.lang.OutOfMemoryError: Java heap space in my app. I am pretty new to profiling java apps using Eclipse Memory Analyzer.
In the Image, it is clear that calling JNI Local has Maximum Retained Heap, But we don't have any JNI calls in our app.
Please review and confirm whether the Memory Leak is caused by calling any Native code (JNI Local) or by using any string iterations or anything else?
for reference here I am attaching total overview and stacktrace of .hprof file:
Accumulated Objects by Class
Label Number of Objects Used Heap Size Retained Heap Size
java.lang.String
First 10 of 15,252,128 objects 15,252,128 488,068,096 2,317,743,632
Thread Details
Thread WorkManager(2)-8
Thread Properties
Object / Stack Frame java.lang.Thread # 0x69af09608
Name WorkManager(2)-8
Shallow Heap 112
Retained Heap 2,384,942,672
Context Class Loader org.jboss.util.loading.DelegatingClassLoader # 0x6912bf868
Is Daemon true
Total: 6 entries
Thread Stack
WorkManager(2)-8
at java.lang.StringCoding.decode(Ljava/lang/String;[BII)[C (StringCoding.java:185)
at java.lang.String.<init>([BIILjava/lang/String;)V (String.java:451)
at java.lang.String.<init>([BLjava/lang/String;)V (String.java:523)
at java.io.UnixFileSystem.list(Ljava/io/File;)[Ljava/lang/String; (Native Method)
at java.io.File.list()[Ljava/lang/String; (File.java:990)
at java.io.File.listFiles(Ljava/io/FilenameFilter;)[Ljava/io/File; (File.java:1107)
at com.adobe.idp.dsc.service.file.impl.WatchedFolderUtils.resolveDuplicateFile(Ljava/lang/String;Z)Ljava/io/File; (WatchedFolderUtils.java:515)
at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.resolveDestination(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Z)Ljava/io/File; (FileResultHandlerImpl.java:308)
at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.preserveFiles(Lcom/adobe/idp/dsc/registry/infomodel/Endpoint;Ljava/lang/String;Ljava/lang/String;)V (FileResultHandlerImpl.java:817)
at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.saveResults(Lcom/adobe/idp/dsc/InvocationResponse;Lcom/adobe/idp/dsc/registry/infomodel/Endpoint;Ljava/lang/String;Ljava/lang/String;)V (FileResultHandlerImpl.java:493)
at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.handleSuccess(Ljava/lang/Object;Ljava/util/Map;)V (FileResultHandlerImpl.java:104)
at com.adobe.idp.dsc.provider.service.file.write.impl.FileResultHandlerImpl.handleSuccess(Lcom/adobe/idp/dsc/InvocationResponse;)V (FileResultHandlerImpl.java:73)
at sun.reflect.GeneratedMethodAccessor2229.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:616)
at com.adobe.idp.dsc.component.impl.DefaultPOJOInvokerImpl.invoke(Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (DefaultPOJOInvokerImpl.java:118)
at com.adobe.idp.dsc.interceptor.impl.InvocationInterceptor.intercept(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;Lcom/adobe/idp/dsc/interceptor/RequestInterceptorChain;)Lcom/adobe/idp/dsc/InvocationResponse; (InvocationInterceptor.java:140)
at com.adobe.idp.dsc.interceptor.impl.RequestInterceptorChainImpl.proceed(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (RequestInterceptorChainImpl.java:60)
at com.adobe.idp.dsc.interceptor.impl.DocumentPassivationInterceptor.intercept(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;Lcom/adobe/idp/dsc/interceptor/RequestInterceptorChain;)Lcom/adobe/idp/dsc/InvocationResponse; (DocumentPassivationInterceptor.java:53)
at com.adobe.idp.dsc.interceptor.impl.RequestInterceptorChainImpl.proceed(Lcom/adobe/idp/dsc/component/ComponentContext;Lcom/adobe/idp/dsc/InvocationRequest;)Lcom/adobe/idp/dsc/InvocationResponse; (RequestInterceptorChainImpl.java:60)
at com.adobe.idp.dsc.transaction.interceptor.TransactionInterceptor$1.doInTransaction(Lcom/adobe/idp/dsc/transaction/TransactionContext;)Ljava/lang/Object; (TransactionInterceptor.java:74)
at com.adobe.idp.dsc.transaction.impl.ejb.adapter.EjbTransactionCMTAdapterBean.execute(Lcom/adobe/idp/dsc/transaction/TransactionContext;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionCMTAdapterBean.java:357)
at com.adobe.idp.dsc.transaction.impl.ejb.adapter.EjbTransactionCMTAdapterBean.doSupports(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionCMTAdapterBean.java:227)
at sun.reflect.GeneratedMethodAccessor698.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Ljava/lang/Object;[Ljava/lang/Object;)Ljava/lang/Object; (Method.java:616)
at org.jboss.invocation.Invocation.performCall(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (Invocation.java:386)
at org.jboss.ejb.StatelessSessionContainer$ContainerInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (StatelessSessionContainer.java:233)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (CachedConnectionInterceptor.java:156)
at org.jboss.ejb.plugins.StatelessSessionInstanceInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (StatelessSessionInstanceInterceptor.java:173)
at org.jboss.ejb.plugins.CallValidationInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (CallValidationInterceptor.java:63)
at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (AbstractTxInterceptor.java:121)
at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (TxInterceptorCMT.java:378)
at org.jboss.ejb.plugins.TxInterceptorCMT.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (TxInterceptorCMT.java:181)
at org.jboss.ejb.plugins.SecurityInterceptor.process(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (SecurityInterceptor.java:228)
at org.jboss.ejb.plugins.SecurityInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (SecurityInterceptor.java:211)
at org.jboss.ejb.plugins.security.PreSecurityInterceptor.process(Lorg/jboss/invocation/Invocation;Z)Ljava/lang/Object; (PreSecurityInterceptor.java:97)
at org.jboss.ejb.plugins.security.PreSecurityInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (PreSecurityInterceptor.java:81)
at org.jboss.ejb.plugins.LogInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (LogInterceptor.java:205)
at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (ProxyFactoryFinderInterceptor.java:138)
at org.jboss.ejb.SessionContainer.internalInvoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (SessionContainer.java:650)
at org.jboss.ejb.Container.invoke(Lorg/jboss/invocation/Invocation;)Ljava/lang/Object; (Container.java:1092)
at org.jboss.ejb.plugins.local.BaseLocalProxyFactory.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (BaseLocalProxyFactory.java:436)
at org.jboss.ejb.plugins.local.StatelessSessionProxy.invoke(Ljava/lang/Object;Ljava/lang/reflect/Method;[Ljava/lang/Object;)Ljava/lang/Object; (StatelessSessionProxy.java:103)
at $Proxy289.doSupports(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (Unknown Source)
at com.adobe.idp.dsc.transaction.impl.ejb.EjbTransactionProvider.execute(Lcom/adobe/idp/dsc/transaction/TransactionDefinition;Lcom/adobe/idp/dsc/transaction/TransactionCallback;)Ljava/lang/Object; (EjbTransactionProvider.java:104)

Your stacktrace shows the method UnixFileSystem.list(File) which is a native method and it’s creating a string array for storing the file names. The remaining question is why it is creating an array of size 16 million. The method starts with an array of size 16 and will double it once the directory scan has more iterations than the array size. So the number of iterations now are between 8 million and 16 million. You either have that unbelievable number of files in that directory or there is a problem in the loop termination condition in that native code.

java.lang.OutOfMemoryError: Java heap space:Trying to use jasper exportreport method

Getting memory out of error while using jaspers exportreport method. The stack trace is given below.
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.text.RuleBasedBreakIterator.readFile(Unknown Source)
at java.text.RuleBasedBreakIterator.readTables(Unknown Source)
at java.text.RuleBasedBreakIterator.<init>(Unknown Source)
at java.text.BreakIterator.createBreakInstance(Unknown Source)
at java.text.BreakIterator.getBreakInstance(Unknown Source)
at java.text.BreakIterator.getLineInstance(Unknown Source)
at java.text.BreakIterator.getLineInstance(Unknown Source)
at java.awt.font.LineBreakMeasurer.<init>(Unknown Source)
at net.sf.jasperreports.engine.fill.TextMeasurer.renderParagraph(TextMeasurer.java:655)
at net.sf.jasperreports.engine.fill.TextMeasurer.measure(TextMeasurer.java:367)
at net.sf.jasperreports.engine.fill.JRFillTextElement.chopTextElement(JRFillTextElement.java:511)
at net.sf.jasperreports.engine.fill.JRFillTextField.prepare(JRFillTextField.java:607)
at net.sf.jasperreports.engine.fill.JRFillElementContainer.prepareElements(JRFillElementContainer.java:328)
at net.sf.jasperreports.engine.fill.JRFillBand.fill(JRFillBand.java:393)
at net.sf.jasperreports.engine.fill.JRFillBand.fill(JRFillBand.java:352)
at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillColumnBand(JRVerticalFiller.java:2023)
at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillDetail(JRVerticalFiller.java:755)
at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReportContent(JRVerticalFiller.java:285)
at net.sf.jasperreports.engine.fill.JRVerticalFiller.fillReport(JRVerticalFiller.java:132)
at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:836)
at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:765)
at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:84)
at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:624)
at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager.java:540)
at com.aricent.aircell.logpatternanalyzer.report.JasperReportUtils.exportReport(JasperReportUtils.java:86)
Also I have tried memory leak analyser and as well as jvisualvm to find out the root cause, but it shows char[] occupying more than 90%. how to find out the exact root cause of this problem.

Seems like the Xmx settings is the problem. You should make sure that it's set high enough. If you suspect that anything else might be the problem you can always create a heapdump when you run oom and check that there is no leaking objects. This can be done by adding two parameters.
-XX:+HeapDumpOnOutOfMemoryError
-XX:HeapDumpPath=/path/to/heapdump
You can then analyze it with jvisualvm or Eclipse MAT (Memory Analyzer Tool)

Have you tried to increase the heap size (Xmx)? It could happen that the report export simply need more memory. Is it working for smaller reports?

Are you try to use Virtualizer for fillReport?
http://community.jaspersoft.com/questions/520261/large-report-virtualizer-solution