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I have a contract code which have getter and setter method.

I have written a java main class which done followings

TransactionReceipt receipt = sendTxAndWait(new byte[0], Hex.decode(metadata.bin));
byte[] contractAddress = receipt.getTransaction().getContractAddress();
CallTransaction.Contract contract = new CallTransaction.Contract(metadata.abi);
CallTransaction.Function inc = contract.getByName("set");
byte[] functionCallBytes = inc.encode(123);
TransactionReceipt receipt1 = sendTxAndWait(contractAddress, functionCallBytes);

Another class having below:

TransactionReceipt receipt = sendTxAndWait(new byte[0], Hex.decode(metadata.bin));
byte[] contractAddress = receipt.getTransaction().getContractAddress();
CallTransaction.Contract contract = new CallTransaction.Contract(metadata.abi);

ProgramResult r = ethereum.callConstantFunction(Hex.toHexString(contractAddress), contract.getByName("get"));
Object[] ret = contract.getByName("get").decodeResult(r.getHReturn());
System.out.println("Current contract data member value: " + ret[0]);

ProgramResult r1 = ethereum.callConstantFunction("823555f52655029e4269ccc8de2bf5d5b83936a8", contract.getByName("get"));
Object[] ret1 = contract.getByName("get").decodeResult(r1.getHReturn());
System.out.println("Executed contract data member value: " + ret1[0]);**

These two are running in two different JVM. now running second program give me output like below: Current contract data member value: 0 Executed contract data member value: 123

Now this "823555f52655029e4269ccc8de2bf5d5b83936a8" is the contract address resolved while creating contract by first java class.

So is it like that, every node want to access a contract member value should know the contract address. or is there any other way to access contract member value in ethereumj client?

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Currently there is no other way of reffering to a contract than by it's address. This is not even a EthereumJ problem but its the way it works for the whole Ethereum Contract world.
Compare a smart contract address to a IP address. They are both machine readable and understandable but they are not easy for humans to get. Therefore your uncertainty.
Generally humans will interact over a web interface through the Mist Browser, Metamask or web3js with a smart contract. This means that they do not need to know the contract address as it is coded into the web page. Said that, I consider a domain naming service for contracts a usefull thing to have and a smart contract doing this is certainly prototyped.

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