synchronized (Nxt.transactions) {
/ if not breaking any logic, loop that contains removing, is better start from end
/     Not sure about Java and this code, but some programs may get critical problems, if removing causes kind of skipping over every second item.

for (int i = block.numberOfTransactions - 1; i >= 0 ; i--) {
//for (int i = 0; i < block.numberOfTransactions; i++) {

Transaction transaction = Nxt.transactions.remove(block.transactions[i]);
unconfirmedTransactions.put(block.transactions[i], transaction);

Account senderAccount = accounts.get(Account.getId(transaction.senderPublicKey));
// check if null?
synchronized (senderAccount) {

senderAccount.setBalance(senderAccount.balance + (transaction.amount + transaction.fee) * 100L);

}



----------------------------

----------------

block.blockSignature = Crypto.sign(data2, secretPhrase);

// inside if block: JSONObject request = block.getJSONObject(newTransactions);
//                  request.put("requestType", "processBlock");
// similarly could be eg. in "  case "sendMoney": ", etc.

if (block.verifyBlockSignature() && block.verifyGenerationSignature()) {
JSONObject request = block.getJSONObject(newTransactions);  / moved here
request.put("requestType", "processBlock");

Peer.sendToAllPeers(request);

} else {


--------------------

synchronized (Nxt.transactions) {

for (int i = 0; i < numberOfTransactions; i++) {

Transaction transaction = Nxt.transactions.get(transactions[i]);

long sender = Account.getId(transaction.senderPublicKey);
Account senderAccount = accounts.get(sender);
//  check if (senderAccount == null) {

synchronized (senderAccount) {


-------------------




long twofoldCurBaseTarget = curBaseTarget * 2;
if (twofoldCurBaseTarget < 0) {  
// also this?    twofoldCurBaseTarget > maxBaseTarget

twofoldCurBaseTarget = maxBaseTarget;

}

if (newBaseTarget > twofoldCurBaseTarget) {


------------------



byte[] getBytes() {

ByteBuffer buffer = ByteBuffer.allocate(4 + 4 + 8 + 4 + 4 + 4 + 4 + 32 + 32 + 64 + 64);
// Did Java take care about low memory or allocation errors? No need to check ?



------------




Account account = accounts.get(Account.getId(generatorPublicKey));
if (account == null || account.getEffectiveBalance() == 0) {

return false;

}
int elapsedTime = timestamp - previousBlock.timestamp;

// does target get here random numbers? Any test results of N*1000 run cases?
BigInteger target = BigInteger.valueOf(Block.getBaseTarget()).multiply(BigInteger.valueOf(account.getEffectiveBalance())).multiply(BigInteger.valueOf(elapsedTime));
byte[] generationSignatureHash = MessageDigest.getInstance("SHA-256").digest(generationSignature);

--------------------------



int getWeight() {
// ...

// if balance < 100, the result should be 0?  
return (int)(adjustedWeight * (account.balance 100) 1000000000);



-------------------------



for (i = 0; i < numberOfBlocks; i++) {
JSONObject blockData = (JSONObject)nextBlocks.get(i);
Block block = Block.getBlock(blockData);
// if block is null ?
curBlockId = block.getId();


----------------------------



synchronized (blocks) {

long blockId = lastBlock;
int height = Block.getLastBlock().height;
int numberOfBlocks = 0;
while (numberOfBlocks < 60) {  
// can height become negative in loop?

numberOfBlocks++;

Block block = blocks.get(blockId);



-----------------------------