Core

var jsonConfig = "";
var ji = JsonIterator.parse(jsonConfig);
var signer = PrivateKeyEncoding.fromJsonPrivateKey(ji);

[1,2,3, ... ,42]

{
  "pubKey": "<BASE58_ENCODED_PUBLIC_KEY>",
  "encoding": "jsonKeyPairArray",
  "secret": []
}

{
  "pubKey": "<BASE58_ENCODED_PUBLIC_KEY>",
  "encoding": "base64KeyPair",
  "secret": "asdf=="
}

{
  "pubKey": "<BASE58_ENCODED_PUBLIC_KEY>",
  "encoding": "base64PrivateKey",
  "secret": "asdf=="
}

byte[] legacyTransactionData = ...;
var skeleton = TransactionSkeleton.deserializeSkeleton(legacyTransactionData);
AccountMeta[] accounts = skeleton.parseAccounts();
Instruction[] instructions = skeleton.parseLegacyInstructions();
Transaction transaction = skeleton.createTransaction()

byte[] v0TransactionData = ...;
var skeleton = TransactionSkeleton.deserializeSkeleton(v0TransactionData);
var instructionsWithoutTableAccounts = skeleton.parseInstructionsWithoutTableAccounts();

PublicKey[] tableAccounts =  skeleton.lookupTableAccounts();
// ... Fetch table accounts (See RPC) ...
AddressLookupTable lookupTable = ...;
AccountMeta[] accounts = skeleton.parseAccounts(lookupTable);
Instruction[] instructions = skeleton.parseInstructions(accounts);
Transaction transaction = skeleton.createTransaction(instructions, lookupTable);