Sync in runPrivate

[Moha66]

When I make a runPrivate it shows me that Sync is disable in the ethereum-harmony interface.
How can I make it work?, so I can upload a contract. Also I don't know what is the different between fast and long Sync?

Thank you.

[zilm13]

@Moha66 if you want to enable sync you could either change sync.enabled property in private.conf config or pass it via command line by adding this flag override: -Dsync.enabled=true

Fast sync is generally designed for big networks like Ethereum Mainnet to reduce synchronization time. Instead of downloading block one by one and executing every tx to get the state of current height in fastsync your client downloads state snapshot near the HEAD of current network, verifies it and switches to regular sync. Usually it's not needed in private networks.

To deploy contract you need to send tx with contract deployment to the network. You could create it either from code using ethereumj or using json-rpc:
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_compilesolidity
https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sendtransaction

[3Mohammed2013]

@zilm13 what I understand from you that , we usually do not need to be fully sync in the private networks , we could deploy the contract by using those eth_compileSolidity , eth_sendTransaction in the json-rpc

but, the second option i do not understanding which using ethereumj

could you please correct me , and explain the ethereumj how could we do that