Hi!
  By release the hashmap, I mean that you need to remove the keys at some
points. Meaning hashMap.remove(key). If you just use hashMap.put() in the
nextTuple method of the spout or in the execute method of the bolt, and
never use the hashMap.remove() and your hashMap is a field in the Bolt or
Spout class, then your map will grow and you'll reach your heap Size.
 The issue that yo have with the jvisualvm is that you have installed only
the Java Runtime Evironment (only the java vm) but not the the JDK (Java
Development Kit) . Please install the JDK.
After installing look at hashmap classes. Check the memory size for them.
Run GC and check if the memort size for them grows. If they grow even after
GC then you could have a memory leak.

I hope that it helps.
 Florin



On Wed, Apr 6, 2016 at 8:49 AM, sam mohel <[email protected]> wrote:

> @florin
> i used this command  java -XX:+PrintFlagsFinal -version | grep HeapSize
>
> and got
>
> uintx ErgoHeapSizeLimit                         = 0
> {product}
>     uintx HeapSizePerGCThread                       = 87241520
> {product}
>     uintx InitialHeapSize                          := 63056640
> {product}
>     uintx LargePageHeapSizeThreshold                = 134217728
> {product}
>     uintx MaxHeapSize                              := 1010827264
> {product}
>
> On Wed, Apr 6, 2016 at 12:44 AM, sam mohel <[email protected]> wrote:
>
>> sorry i forgot to mention that my ram is 3.8 GB and i used hahsmap in the
>> code but i don't know what do you mean by release it ?
>>
>>
>> On Wed, Apr 6, 2016 at 12:20 AM, sam mohel <[email protected]> wrote:
>>
>>> @ florin thanks for replying , i installed tool but got when i ran it
>>> i checked update-alternatives --config java
>>> There are 3 choices for the alternative java (providing /usr/bin/java).
>>>
>>>   Selection    Path
>>> Priority   Status
>>> ------------------------------------------------------------
>>>   0            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
>>> 1071      auto mode
>>> * 1            /usr/lib/jvm/java-6-openjdk-amd64/jre/bin/java
>>> 1061      manual mode
>>>   2            /usr/lib/jvm/java-6-oracle/jre/bin/java
>>> 1062      manual mode
>>>   3            /usr/lib/jvm/java-7-openjdk-amd64/jre/bin/java
>>> 1071      manual mode
>>>
>>>
>>>
>>> ​
>>>
>>> On Sun, Apr 3, 2016 at 9:19 PM, Spico Florin <[email protected]>
>>> wrote:
>>>
>>>> hi!
>>>> before increasing the ram (by rpoviding in command line arguments the
>>>> jvm options java -Xmx) try to use a profile tool such as jvisualvm jprobe
>>>> to see if you have amemory leak. do you use a cache (for example hashmap
>>>> where you store some data but never relese it). how much ram do you have on
>>>> your machine? check your default heap size with the help of this link
>>>>
>>>> http://stackoverflow.com/questions/4667483/how-is-the-default-java-heap-size-determined
>>>> regards florin
>>>>
>>>>
>>>>
>>>> On Sunday, April 3, 2016, sam mohel <[email protected]> wrote:
>>>> > do you mean in storm.yaml ? or where ?
>>>> >
>>>> > On Sun, Apr 3, 2016 at 11:56 AM, Andrey Dudin <[email protected]>
>>>> wrote:
>>>> >>
>>>> >> Try to extra more RAM for this topology.
>>>> >> -Xms and -Xmx options
>>>> >>
>>>> >> 2016-04-03 1:32 GMT+03:00 sam mohel <[email protected]>:
>>>> >>>
>>>> >>> i'm facing problem with topology i ran it in local mode and got
>>>> >>> Async loop died!java.lang.OutOfMemoryError: GC overhead limit
>>>> exceeded
>>>> >>>
>>>> >>> Can you help on this ? if there is any data you need for helping
>>>> just tell me
>>>> >>>
>>>> >>> Thanks in advance
>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> С уважением Дудин Андрей
>>>> >
>>>>
>>>
>>>
>>
>

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