Not able to add 'replayPastTransactionsFlowable' transaction logs result into an collection List object using Web3j java?

Question

I'm trying to create an api where i have to provide transaction logs in json objects but im unable to add result of replayPastTransactionsFlowable into an collection object

    @GetMapping("/test")
public List<Transaction> test() throws InterruptedException, ExecutionException, IOException {
    String address = "0xeedc155ae507fb0a9becae6315286183a23229b0";
    List<Transaction> transactions = new ArrayList<Transaction>();
    Web3j web3j = web3jConfig.initializeWeb3j();
    System.out.println("test Running.......");
    BigInteger block = web3j.ethBlockNumber().send().getBlockNumber();
    System.out.println("blockno:" + block.intValue());
    int block_no = block.intValue();


Flowable<Transaction> replyBlocks   = web3j.replayPastTransactionsFlowable(DefaultBlockParameterName.EARLIEST, DefaultBlockParameterName.LATEST);
replyBlocks.forEach(temp->{
    System.out.println("into replyBlocks");
    System.out.println(temp.getBlockNumber());
        transactions.add(temp); //It's an collection object,and value is not adding into it 
})  ;

    return transactions;
}

} Im using following two dep

    <dependency>
        <groupId>org.web3j</groupId>
        <artifactId>core</artifactId>
        <version>4.5.5</version>
    </dependency>

    <dependency>
        <groupId>org.web3j</groupId>
        <artifactId>contracts</artifactId>
        <version>4.5.5</version>
    </dependency>

Answer 1

Try this

import java.math.BigInteger;

import org.springframework.web.bind.annotation.*;
import org.web3j.protocol.Web3j;
import org.web3j.protocol.core.DefaultBlockParameterName;
import org.web3j.protocol.core.methods.response.Transaction;
import org.web3j.protocol.core.methods.response.Web3ClientVersion;
import org.web3j.protocol.http.HttpService;

import io.reactivex.Flowable;

@RestController
@RequestMapping("/api")
public class SimpleResource {

    @GetMapping("/transactions")
    public Flowable<Transaction> getTransactions() throws Exception {
        System.out.println("call transactions");
        Web3j web3j = Web3j.build(new HttpService());
        Web3ClientVersion web3ClientVersion = web3j.web3ClientVersion().send();
        String clientVersion = web3ClientVersion.getWeb3ClientVersion();
        System.out.println("clientVersion......." + clientVersion);
        BigInteger block = web3j.ethBlockNumber().send().getBlockNumber();
        System.out.println("blockno:" + block.intValue());
        Flowable<Transaction> transactions =  web3j.replayPastTransactionsFlowable(DefaultBlockParameterName.EARLIEST,
                DefaultBlockParameterName.LATEST).serialize();
        return  transactions;
    }
}