[pull] master from bitcoinj:master

examples/src/main/java/org/bitcoinj/examples/FetchBlock.java

@@ -30,8 +30,10 @@
 import org.bitcoinj.store.BlockStore;
 import org.bitcoinj.store.MemoryBlockStore;
 import org.bitcoinj.utils.BriefLogFormatter;
+import org.jspecify.annotations.Nullable;
 import picocli.CommandLine;
 
+import java.util.Objects;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Future;
 
@@ -44,7 +46,7 @@
 @CommandLine.Command(usageHelpAutoWidth = true, sortOptions = false)
 public class FetchBlock implements Callable<Integer> {
     @CommandLine.Parameters(index = "0", description = "The hash of the block to download.")
-    private String blockHashParam;
+    private @Nullable String blockHashParam;
     @CommandLine.Option(names = "--localhost", description = "Connect to the localhost node. Default: ${DEFAULT-VALUE}")
     private boolean localhost = true;
     @CommandLine.Option(names = "--help", usageHelp = true, description = "Displays program options.")
@@ -59,6 +61,7 @@ public static void main(String[] args) throws Exception {
     @Override
     public Integer call() throws Exception {
         // Connect to testnet and find a peer
+        Objects.requireNonNull(blockHashParam);
         System.out.println("Connecting to node");
         final Network network = BitcoinNetwork.TESTNET;
         final NetworkParameters params = NetworkParameters.of(network);

examples/src/main/java/org/bitcoinj/examples/ForwardingService.java

@@ -29,6 +29,7 @@
 import org.bitcoinj.wallet.SendRequest;
 import org.bitcoinj.wallet.Wallet;
 import org.bitcoinj.wallet.listeners.WalletCoinsReceivedEventListener;
+import org.jspecify.annotations.Nullable;
 
 import java.io.Closeable;
 import java.io.File;
@@ -46,7 +47,7 @@ public class ForwardingService implements Closeable {
     static final int MAX_CONNECTIONS = 4;
     private final BitcoinNetwork network;
     private final Address forwardingAddress;
-    private volatile WalletAppKit kit;
+    private volatile @Nullable WalletAppKit kit;
     /* We need to save the listener object (created by a method reference) so we can remove it later */
     private final WalletCoinsReceivedEventListener coinsReceivedListener = this::coinForwardingListener;
 

examples/src/main/java/org/bitcoinj/examples/GenerateLowSTests.java

@@ -38,6 +38,7 @@
 import org.bitcoinj.signers.TransactionSigner.ProposedTransaction;
 import org.bitcoinj.wallet.KeyBag;
 import org.bitcoinj.wallet.RedeemData;
+import org.jspecify.annotations.Nullable;
 
 import java.io.IOException;
 import java.math.BigInteger;
@@ -75,6 +76,7 @@ public ECKey findKeyFromPubKey(byte[] pubKey) {
             }
 
             @Override
+            @Nullable
             public RedeemData findRedeemDataFromScriptHash(byte[] scriptHash) {
                 return null;
             }

examples/src/main/java/org/bitcoinj/examples/PrintPeers.java

@@ -18,6 +18,7 @@
 
 import org.bitcoinj.base.BitcoinNetwork;
 import org.bitcoinj.base.Network;
+import org.bitcoinj.core.Context;
 import org.bitcoinj.core.NetworkParameters;
 import org.bitcoinj.core.Peer;
 import org.bitcoinj.core.PeerAddress;
@@ -33,55 +34,55 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
+import java.util.logging.Level;
 
 /**
  * Prints a list of IP addresses obtained from DNS.
  */
 public class PrintPeers {
-    private static List<InetSocketAddress> dnsPeers;
+    record PeerDnsResult(List<InetSocketAddress> dnsPeers, Duration duration) {}
 
-    private static void printElapsed(long start) {
-        long now = System.currentTimeMillis();
-        System.out.println(String.format("Took %.2f seconds", (now - start) / 1000.0));
-    }
-
-    private static void printPeers(List<InetSocketAddress> addresses) {
-        for (InetSocketAddress address : addresses) {
+    private static void printPeers(PeerDnsResult result) {
+        for (InetSocketAddress address : result.dnsPeers()) {
             String hostAddress = address.getAddress().getHostAddress();
             System.out.println(String.format("%s:%d", hostAddress, address.getPort()));
         }
+        System.out.println(String.format("DNS query took %.2f seconds", result.duration().toMillis() / 1000.0));
     }
 
-    private static void printDNS(Network network) throws PeerDiscoveryException {
+    private static PeerDnsResult getPeers(Network network) throws PeerDiscoveryException {
         long start = System.currentTimeMillis();
         DnsDiscovery dns = new DnsDiscovery(network);
-        dnsPeers = dns.getPeers(0, Duration.ofSeconds(10));
-        printPeers(dnsPeers);
-        printElapsed(start);
+        List<InetSocketAddress> dnsPeers = dns.getPeers(0, Duration.ofSeconds(10));
+        var duration = Duration.ofMillis(System.currentTimeMillis() - start);
+        return new PeerDnsResult(dnsPeers, duration);
     }
 
     public static void main(String[] args) throws Exception {
-        BriefLogFormatter.init();
+        BriefLogFormatter.init(Level.WARNING);
+        Context.propagate(new Context());
         final Network network = BitcoinNetwork.MAINNET;
         final NetworkParameters params = NetworkParameters.of(network);
         System.out.println("=== DNS ===");
-        printDNS(network);
+        PeerDnsResult result = getPeers(network);
+        printPeers(result);
         System.out.println("=== Version/chain heights ===");
 
         ArrayList<InetAddress> addrs = new ArrayList<>();
-        for (InetSocketAddress peer : dnsPeers) addrs.add(peer.getAddress());
+        for (InetSocketAddress peer : result.dnsPeers()) addrs.add(peer.getAddress());
         System.out.println("Scanning " + addrs.size() + " peers:");
 
         final Object lock = new Object();
         final long[] bestHeight = new long[1];
 
-        List<CompletableFuture<Void>> futures = new ArrayList<>();
+        List<CompletableFuture<Boolean>> futures = new ArrayList<>();
         NioClientManager clientManager = new NioClientManager();
+        clientManager.start().join();
         for (final InetAddress addr : addrs) {
             InetSocketAddress address = new InetSocketAddress(addr, params.getPort());
             final Peer peer = new Peer(params, new VersionMessage(params, 0),
                     PeerAddress.simple(address), null);
-            final CompletableFuture<Void> future = new CompletableFuture<>();
+            final CompletableFuture<Boolean> future = new CompletableFuture<>();
             // Once the connection has completed version handshaking ...
             peer.addConnectedEventListener((p, peerCount) -> {
                 // Check the chain height it claims to have.
@@ -100,18 +101,22 @@ public static void main(String[] args) throws Exception {
                     }
                 }
                 // Now finish the future and close the connection
-                future.complete(null);
+                future.complete(true);
                 peer.close();
             });
             peer.addDisconnectedEventListener((p, peerCount) -> {
-                if (!future.isDone())
+                if (!future.isDone()) {
                     System.out.println("Failed to talk to " + addr);
-                future.complete(null);
+                    future.complete(false);
+                }
             });
             clientManager.openConnection(address, peer);
             futures.add(future);
         }
         // Wait for every tried connection to finish.
         CompletableFuture.allOf(futures.toArray( new CompletableFuture[0])).join();
+        int successful = futures.stream().mapToInt(f -> f.join() ? 1 : 0).sum();
+        int total = futures.size();
+        System.out.printf("Successfully talked to %d of %d nodes.\n", successful, total);
     }
 }

examples/src/main/java/org/bitcoinj/examples/package-info.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright by the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * <b>bitcoinj<b> example applications including {@link org.bitcoinj.examples.ForwardingService} which
+ * is featured in the <b>Getting Started</b> tutorial.
+ * @see <a href="https://bitcoinj.org/getting-started-java">Getting Started</a>
+ */
+@NullMarked
+package org.bitcoinj.examples;
+
+import org.jspecify.annotations.NullMarked;