AEM OutOfMemoryError: Java heap space or OutOfMemoryError: gc overhead limit exceeded.

Heap histogram

• The heap histogram is a simple measurement of the number of live objects and memory used per Java class. 
• To create a heap histogram, you first need the process id of the Java process. To get it, run ps or (if available), run:

              jps -l

This Java tool gets the process ids of all running Java processes. Example:

          327 
          3332 sun.tools.jps.Jps
          3313 crx-quickstart-....jar

Now run the following command:

        jmap -histo 3313

• The list is sorted by total memory required (shallow: excluding referenced objects). 
• The first 20 lines of the output are the most interesting. Example output:

JVM version is 1.5.0_20-141
Iterating over heap. This may take a while...
Warning: skipping invalid TLAB for thread t@62211
Warning: skipping invalid TLAB for thread t@62467
...
Size Count Class description
-------------------------------------------------------
10592904 12916 byte[]
10285840 75255 * ConstMethodKlass
6283176 58388 char[]
6042304 14928 int[]
4995752 116201 * SymbolKlass
4220896 75255 * MethodKlass
4196512 6969 * ConstantPoolKlass
2928560 6969 * InstanceKlassKlass
2631008 6066 * ConstantPoolCacheKlass
2395872 149742 org.apache.jackrabbit.core.query.lucene.DocId$PlainDocId
1476008 7003 java.util.HashMap$Entry[]
1396128 58172 java.lang.String
1070232 44593 java.util.HashMap$Entry
753984 10036 short[]
735464 54 org.apache.jackrabbit.core.query.lucene.DocId[]
720192 7502 java.lang.Class
640704 13348 com.day.crx.persistence.tar.index.IndexEntry
...

Additional information

To help analyzing the problem, we also need to know the following information:

• CRX or CQ version, including a listing of all installed hot fixes version number.
• Operating system, JVM vendor, and version.

Reference URL :

https://helpx.adobe.com/experience-manager/kb/AnalyzeMemoryProblems.html