Add send transaction with external sign

pom.xml

@@ -18,7 +18,7 @@
         <connection>scm:git:git://github.com/skynetcap/solanaj.git</connection>
         <developerConnection>scm:git:ssh://github.com/skynetcap/solanaj.git</developerConnection>
         <url>https://github.com/skynetcap/solanaj/tree/main</url>
-    </scm>  
+    </scm>
     <developers>
         <developer>
             <name>Michael Morrell</name>
@@ -42,7 +42,7 @@
         <dependency>
             <groupId>org.bitcoinj</groupId>
             <artifactId>bitcoinj-core</artifactId>
-            <version>0.16.3</version>
+            <version>0.17</version>
             <exclusions>
                 <exclusion>
                     <groupId>com.google.protobuf</groupId>

src/main/java/org/p2p/solanaj/core/Account.java

@@ -5,7 +5,7 @@
 import java.util.List;
 
 import org.bitcoinj.crypto.*;
-import org.bitcoinj.core.Base58;
+import org.bitcoinj.base.Base58;
 import org.p2p.solanaj.utils.TweetNaclFast;
 import org.p2p.solanaj.utils.bip32.wallet.SolanaBip44;
 import org.p2p.solanaj.utils.bip32.wallet.DerivableType;
@@ -30,7 +30,7 @@ public static Account fromMnemonic(List<String> words, String passphrase) {
         byte[] seed = MnemonicCode.toSeed(words, passphrase);
         DeterministicKey masterPrivateKey = HDKeyDerivation.createMasterPrivateKey(seed);
         DeterministicHierarchy deterministicHierarchy = new DeterministicHierarchy(masterPrivateKey);
-        DeterministicKey child = deterministicHierarchy.get(HDUtils.parsePath("M/501H/0H/0/0"), true, true);
+        DeterministicKey child = deterministicHierarchy.get(HDPath.parsePath("M/501H/0H/0/0"), true, true);
         TweetNaclFast.Signature.KeyPair keyPair = TweetNaclFast.Signature.keyPair_fromSeed(child.getPrivKeyBytes());
         return new Account(keyPair);
     }

src/main/java/org/p2p/solanaj/core/Message.java

@@ -1,6 +1,6 @@
 package org.p2p.solanaj.core;
 
-import org.bitcoinj.core.Base58;
+import org.bitcoinj.base.Base58;
 import org.p2p.solanaj.utils.ShortvecEncoding;
 
 import java.nio.ByteBuffer;
@@ -41,7 +41,7 @@ int getLength() {
     private String recentBlockhash;
     private AccountKeysList accountKeys;
     private List<TransactionInstruction> instructions;
-    private Account feePayer;
+    private PublicKey feePayerPublicKey;
 
     public Message() {
         this.accountKeys = new AccountKeysList();
@@ -143,8 +143,8 @@ public byte[] serialize() {
         return out.array();
     }
 
-    protected void setFeePayer(Account feePayer) {
-        this.feePayer = feePayer;
+    protected void setFeePayerPublicKey(PublicKey feePayerPublicKey) {
+        this.feePayerPublicKey = feePayerPublicKey;
     }
 
     private List<AccountMeta> getAccountKeys() {
@@ -159,7 +159,7 @@ private List<AccountMeta> getAccountKeys() {
                     .collect(Collectors.toList());
         }
 
-        int feePayerIndex = findAccountIndex(keysList, feePayer.getPublicKey());
+        int feePayerIndex = findAccountIndex(keysList, feePayerPublicKey);
         List<AccountMeta> newList = new ArrayList<AccountMeta>();
         AccountMeta feePayerMeta = keysList.get(feePayerIndex);
         newList.add(new AccountMeta(feePayerMeta.getPublicKey(), true, true));

src/main/java/org/p2p/solanaj/core/PublicKey.java

@@ -7,8 +7,8 @@
 import java.util.List;
 
 import com.fasterxml.jackson.databind.annotation.JsonSerialize;
-import org.bitcoinj.core.Base58;
-import org.bitcoinj.core.Sha256Hash;
+import org.bitcoinj.base.Base58;
+import org.bitcoinj.base.Sha256Hash;
 import org.p2p.solanaj.utils.ByteUtils;
 import org.p2p.solanaj.utils.PublicKeySerializer;
 import org.p2p.solanaj.utils.TweetNaclFast;

src/main/java/org/p2p/solanaj/core/Transaction.java

@@ -5,8 +5,9 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
+import java.util.function.Function;
 
-import org.bitcoinj.core.Base58;
+import org.bitcoinj.base.Base58;
 import org.p2p.solanaj.utils.ShortvecEncoding;
 import org.p2p.solanaj.utils.TweetNaclFast;
 
@@ -76,8 +77,7 @@ public void sign(List<Account> signers) {
         }
 
         Account feePayer = signers.get(0);
-        message.setFeePayer(feePayer);
-
+        message.setFeePayerPublicKey(feePayer.getPublicKey());
         serializedMessage = message.serialize();
 
         for (Account signer : signers) {
@@ -91,6 +91,29 @@ public void sign(List<Account> signers) {
         }
     }
 
+    /**
+     * Signs the transaction with external signer.
+     *
+     * @param feePayerPublicKey - The public key of the signer's account.
+     * @param externalSigner - Function for external sign.
+     * @throws IllegalArgumentException if no signers are provided
+     */
+    public void signByExternalSigner(PublicKey feePayerPublicKey, Function<byte[], byte[]> externalSigner) {
+        if (externalSigner == null) {
+            throw new IllegalArgumentException("No external signer provided");
+        }
+
+        message.setFeePayerPublicKey(feePayerPublicKey);
+        serializedMessage = message.serialize();
+
+        try {
+            byte[] signature = externalSigner.apply(message.serialize());
+            signatures.add(Base58.encode(signature));
+        } catch (Exception e) {
+            throw new RuntimeException("Error signing transaction", e); // Improve exception handling
+        }
+    }
+
     /**
      * Serializes the transaction into a byte array.
      *

src/main/java/org/p2p/solanaj/programs/AssociatedTokenProgram.java

@@ -30,8 +30,9 @@ public class AssociatedTokenProgram extends Program {
      */
     public static TransactionInstruction create(PublicKey fundingAccount,
                                                 PublicKey walletAddress,
-                                                PublicKey mint) {
-        return createInstruction(CREATE_METHOD_ID, fundingAccount, walletAddress, mint);
+                                                PublicKey mint,
+                                                PublicKey tokenProgram) {
+        return createInstruction(CREATE_METHOD_ID, fundingAccount, walletAddress, mint, tokenProgram);
     }
 
     /**
@@ -45,8 +46,9 @@ public static TransactionInstruction create(PublicKey fundingAccount,
      */
     public static TransactionInstruction createIdempotent(PublicKey fundingAccount,
                                                           PublicKey walletAddress,
-                                                          PublicKey mint) {
-        return createInstruction(CREATE_IDEMPOTENT_METHOD_ID, fundingAccount, walletAddress, mint);
+                                                          PublicKey mint,
+                                                          PublicKey tokenProgram) {
+        return createInstruction(CREATE_IDEMPOTENT_METHOD_ID, fundingAccount, walletAddress, mint, tokenProgram);
     }
 
     /**
@@ -66,7 +68,8 @@ public static TransactionInstruction recoverNested(PublicKey nestedAccount,
                                                        PublicKey destinationAccount,
                                                        PublicKey ownerAccount,
                                                        PublicKey ownerMint,
-                                                       PublicKey wallet) {
+                                                       PublicKey wallet,
+                                                       PublicKey tokenProgram) {
         final List<AccountMeta> keys = new ArrayList<>();
 
         keys.add(new AccountMeta(nestedAccount, false, true));
@@ -75,7 +78,7 @@ public static TransactionInstruction recoverNested(PublicKey nestedAccount,
         keys.add(new AccountMeta(ownerAccount, false, false));
         keys.add(new AccountMeta(ownerMint, false, false));
         keys.add(new AccountMeta(wallet, true, true));
-        keys.add(new AccountMeta(TokenProgram.PROGRAM_ID, false, false));
+        keys.add(new AccountMeta(tokenProgram, false, false));
 
         byte[] transactionData = encodeInstructionData(RECOVER_NESTED_METHOD_ID);
 
@@ -85,29 +88,30 @@ public static TransactionInstruction recoverNested(PublicKey nestedAccount,
     private static TransactionInstruction createInstruction(int methodId,
                                                             PublicKey fundingAccount,
                                                             PublicKey walletAddress,
-                                                            PublicKey mint) {
+                                                            PublicKey mint,
+                                                            PublicKey tokenProgram) {
         final List<AccountMeta> keys = new ArrayList<>();
 
-        PublicKey pda = findAssociatedTokenAddress(walletAddress, mint);
+        PublicKey pda = findAssociatedTokenAddress(walletAddress, mint, tokenProgram);
 
         keys.add(new AccountMeta(fundingAccount, true, true));
         keys.add(new AccountMeta(pda, false, true));
         keys.add(new AccountMeta(walletAddress, false, false));
         keys.add(new AccountMeta(mint, false, false));
         keys.add(new AccountMeta(SystemProgram.PROGRAM_ID, false, false));
-        keys.add(new AccountMeta(TokenProgram.PROGRAM_ID, false, false));
+        keys.add(new AccountMeta(tokenProgram, false, false));
 
         byte[] transactionData = encodeInstructionData(methodId);
 
         return createTransactionInstruction(PROGRAM_ID, keys, transactionData);
     }
 
-    private static PublicKey findAssociatedTokenAddress(PublicKey walletAddress, PublicKey mint) {
+    private static PublicKey findAssociatedTokenAddress(PublicKey walletAddress, PublicKey mint, PublicKey tokenProgram) {
         try {
             PublicKey pda = PublicKey.findProgramAddress(
                     List.of(
                             walletAddress.toByteArray(),
-                            TokenProgram.PROGRAM_ID.toByteArray(),
+                            tokenProgram.toByteArray(),
                             mint.toByteArray()
                     ),
                     PROGRAM_ID

src/main/java/org/p2p/solanaj/programs/SystemProgram.java

@@ -55,6 +55,27 @@ public static TransactionInstruction transfer(PublicKey fromPublicKey, PublicKey
         return new TransactionInstruction(PROGRAM_ID, keys, data);
     }
 
+    /** Write 8 bytes to the byte array (starting at the offset) as signed 64-bit integer in little endian format. */
+    public static void int64ToByteArrayLE(long val, byte[] out, int offset) {
+        out[offset] = (byte) (0xFF & val);
+        out[offset + 1] = (byte) (0xFF & (val >> 8));
+        out[offset + 2] = (byte) (0xFF & (val >> 16));
+        out[offset + 3] = (byte) (0xFF & (val >> 24));
+        out[offset + 4] = (byte) (0xFF & (val >> 32));
+        out[offset + 5] = (byte) (0xFF & (val >> 40));
+        out[offset + 6] = (byte) (0xFF & (val >> 48));
+        out[offset + 7] = (byte) (0xFF & (val >> 56));
+    }
+
+
+    /** Write 4 bytes to the byte array (starting at the offset) as unsigned 32-bit integer in little endian format. */
+    public static void uint32ToByteArrayLE(long val, byte[] out, int offset) {
+        out[offset] = (byte) (0xFF & val);
+        out[offset + 1] = (byte) (0xFF & (val >> 8));
+        out[offset + 2] = (byte) (0xFF & (val >> 16));
+        out[offset + 3] = (byte) (0xFF & (val >> 24));
+    }    
+
     /**
      * Creates an instruction to create a new account.
      *