• Login to your Linux/Unix Server
• Enter the below command to get the JAVA PID running on the server.

                          ps –ef|grep –i java

From the output take the application JAVA PID.

• Using jstat command with gc option to find out the JVM Heap Memory Usage.

/bin/jstat –gc

S0C – Current survivor space 0 capacity (KB).
S1C  –  Current survivor space 1 capacity (KB).
S0U – Survivor space 0 utilization (KB).
S1U  – Survivor space 1 utilization (KB).
EC    – Current eden space capacity (KB).
EU    – Eden space utilization (KB).
OC    – Current old space capacity (KB).
OU    – Old space utilization (KB).
PC     – Current permanent space capacity (KB).
PU     – Permanent space utilization (KB).
YGC   – Number of young generation GC Events.
YGCT – Young generation garbage collection time.
FGC   – Number of full GC events.
FGCT – Full garbage collection time.
GCT   – Total garbage collection time.

When you add all the ‘utilizations’ i.e OU + EU + S0U + S1U  you get the total Heap utilization.

Use Below command if you lazy enough to calculate the above and to get Heap utilisation in one command.

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To understand more about jstat utility .please read the article.

https://javaperformance.wordpress.com/2017/07/05/jstat-jvm-performance-monitoring-tool/

Heap Utilization using jmap 

• Enter the below command to get the JAVA PID running on the server.

                          ps –ef|grep –i java

From the output take the application JAVA PID.

• Using jstat command with gc option to find out the JVM Heap Memory Usage.

/bin/jmap –heap

Calculate the Heap Utilisation  by adding the used value of

New Generation (Eden + 1 Survivor Space):
+
concurrent mark-sweep generation:

There are other tools like visualvm, APM tools to get the heap memory usage. If this article found useful please comment and let me know how can i improve.

Read the  latest Post on SSL certificate creation and keytool utility,

https://javaperformance.wordpress.com/2018/12/31/keytool-command-utility-to-generate-a-keystore-certificate-request/

To understand better about Garbage collection please refer below post.

https://javaperformance.wordpress.com/2017/07/05/garbage-collection-in-java/

To know more about JSTAT tool. Please refer to my below post.

https://javaperformance.wordpress.com/2017/07/05/jstat-jvm-performance-monitoringtool/