The javaw.exe process, in regards to ArcGIS Server, is split into two main processes. These provide basic application server functionality and the ability to host web services. Refer to ArcGIS Enterprise: Inside an ArcGIS Server site for more information.
The 'App server maximum heap size' and 'SOC maximum heap size' set the maximum file size (in MB) that can be sent to the GIS Server, as shown in the image below. The heap size refers to the reserved memory allocated for cache to use with a Java application to each of the services. This can be increased if the server has too many instances or is under heavy load. The server maximum heap size can be observed from the ArcGIS Server Administrator Directory.
ArcGIS Server is tuned for optimal performance out-of-the-box; therefore, it is not recommended to change the settings (Advanced Administrator settings) unless necessary. The two main processes of javaw.exe are the entry point into ArcGIS Server (handles requests on ports 6080 and 6443) and are tuned for high performance. After the server starts up and while the system is idle, the machine is prepared to manage high volumes of requests.
When an operation is executed on a service, ArcGIS Server caches the result. Changing the heap size may proportionally change the RAM consumption and CPU utilization on the server, depending on the number of ArcSOC processes and the corresponding RAM consumed by each of the processes, which may impact overall performance. For example, if the default heap size is decreased and the operation is too large for the pre-allocated memory of a particular server object container (SOC) process, the operation may fail due to lack of memory to return the results. If the maximum heap size is increased, it may affect the performance of other applications that utilize the javaw.exe process.
In certain cases, javaw.exe shows high CPU usage if antivirus software interacts with the program. If disabling the antivirus program solves the issue, the following folders must be allow listed to improve performance.