add -jar for java command

[shouhong]

What is the purpose of the change

Fix documentation error.

Brief changelog

add -jar for java command

Verifying this change

Review the document.

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[codecov-io]

Codecov Report

Merging #4517 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #4517      +/-   ##
============================================
- Coverage     62.94%   62.92%   -0.02%     
- Complexity      449      450       +1     
============================================
  Files           770      770              
  Lines         33006    33006              
  Branches       5216     5216              
============================================
- Hits          20774    20769       -5     
- Misses         9835     9843       +8     
+ Partials       2397     2394       -3

Impacted Files	Coverage Δ	Complexity Δ
...ache/dubbo/remoting/p2p/support/AbstractGroup.java	45.45% <0%> (-11.37%)	0% <0%> (ø)
...e/dubbo/remoting/transport/netty/NettyChannel.java	54.11% <0%> (-3.53%)	19% <0%> (-1%)
...pache/dubbo/registry/support/AbstractRegistry.java	78.54% <0%> (-3.07%)	0% <0%> (ø)
...ache/dubbo/registry/multiple/MultipleRegistry.java	64.08% <0%> (+1.4%)	22% <0%> (+2%)	⬆️
...ng/exchange/support/header/HeartbeatTimerTask.java	78.94% <0%> (+5.26%)	0% <0%> (ø)	⬇️
...ache/dubbo/remoting/transport/AbstractChannel.java	87.5% <0%> (+12.5%)	0% <0%> (ø)	⬇️
.../apache/dubbo/qos/protocol/QosProtocolWrapper.java	82.05% <0%> (+17.94%)	0% <0%> (ø)	⬇️

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[htynkn]

Thanks for your contribution.