Follow the below steps:
- Go to the private key file (For geth: AppData/Ethereum/keystore and for eth: AppData/Web3/keys)
- Find the key. It'll something like this:
Ethereum\keystore\UTC--2018-3-14T11-51-50.069518500Z--228fh83c240g512be19d3f28dna5d7f0333jfoim
To create the wallet using web3j:
String fileName = WalletUtils.generateNewWalletFile(
"your password",
new File("/path/to/destination"));
Alternatively, you can use https://www.myetherwallet.com/