This article answers following queries :
ü Can we
restart java stack from abap stack in sap?
ü How to
restart java stack from abap stack in sap?
ü What is
the transaction code used to restart java stack in sap?
ü How to
restart the java stack of an sap netweaver add in installation?
ü How to
restart java stack in an ABAP + Java stack system?
ü How to
restart all java instances of an SAP system from ABAP stack?
ü How to
bring down java stack of an application server from abap level?
ü How to
bring down entire java cluster of an SAP system from ABAP stack?
ü What is
the difference between soft shutdown and hard shut down of java stack in SMICM?
ü What are
the different ways of restarting java stack of an SAP system?
ü Which
java shutdown / restart method should be used in cases of emergency in SAP?
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Yes. Java stack can be restarted from abap stack in sap.
SMICM is the transaction code used to restart the java stack in an ABAP + Java stack system.
Login to abap stack of an SAP system and choose transaction SMICM and navigate to
Administration -> AS Java -> Instance (Local) -> Send soft shutdown -> with restart
Please find below screenshot :
Please note, if restart is not required and if you want to only bring down the java stack then choose without restart option in the above SMICM screen.
Administration -> AS Java -> Instance (Local) -> Send soft shutdown -> without restart
Please note in the above method, we can only restart or bring down local java stack of an instance. If you would like to restart entire java cluster of an sap system (ie. Global), in SMICM transaction, navigate to
Administration -> AS Java -> Cluster (Global) -> Send soft shutdown -> with restart
Please find below screenshot for the same
If you would like to just bring down entire java cluster of an SAP system, then navigate as below in SMICM transaction
Administration -> AS Java -> Cluster (Global) -> Send soft shutdown -> without restart
Also there are 2 methods in restart or bringing down the java stack.
They are
1)Send Soft shutdown : In this method, the abap dispatcher sends a SIGQUIT message to the jstart process. The AS java will be terminated with a soft shutdown. It means, the abap dispatcher will not actively close the connection. It will wait and finish the processing of all the running requests and then shuts down.
2)Send Hard shutdown : In this method, the abap dispatcher sends a SIGINT message to the jstart process. The AS java will be terminated with a hard shutdown. It means, java processes will get some time to close. If that time is not sufficient, they are closed with a hard shut down.
The main difference between soft shut down and hard shut down is the hard shut down will happen quickly within few minutes where as the soft shut down will happen only after completing the processing of all running requests.
Ending the process (with or without a restart) :
We can also bring down or restart java by using the option “End process” in SMICM.
The abap dispatcher sets the restart flag for AS java and sends the SIGKILL signal to the jstart process. This terminates the jstart and the AS java with a hard shut down.
Please note that this option should be used only in emergency as processes shutdown in this way will no longer be able to reach stable state.
Please navigate as below to do the same for local instance.
Administration -> AS Java -> Instance (Local) -> End process -> without restart
Or
Administration -> AS Java -> Instance (Local) -> End process -> with restart
Please navigate as below to bring down or restart java globally for all java clusters.
Administration -> AS Java -> Cluster (Global) -> End Process -> without restart
Or
Administration -> AS Java -> Cluster (Global) -> End Process -> with restart
4 comments:
Ending the process (with or without a restart) :
We can ....
Please note that this option should be used only in emergency as processes shutdown in this way will no longer be able to reach stable state.
What do you mean by processes not able to reach stable state?
form which abap stack , you are restarting which java stack?
Are they both in a single systme?
can u post the sap basis screen shots in linux
Nice printscreens, but usually on java instance issues it is necessary to restart Java instance at OS lvl, clean memory and so on. This will be helpful instead of 3 clicks SMICM
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