Derive AssociatedTokenAddresses just like we do all the other addresses

src/main/java/com/lmax/solana4j/Solana.java

@@ -1,7 +1,6 @@
 package com.lmax.solana4j;
 
 import com.lmax.solana4j.api.AddressLookupTable;
-import com.lmax.solana4j.api.AssociatedTokenAddress;
 import com.lmax.solana4j.api.Blockhash;
 import com.lmax.solana4j.api.InnerTransactionBuilder;
 import com.lmax.solana4j.api.Message;
@@ -121,19 +120,6 @@ public static ProgramDerivedAddress programDerivedAddress(final List<byte[]> see
         return SolanaEncoding.deriveProgramAddress(seeds, programId);
     }
 
-    /**
-     * Derives an associated token address for the given owner, mint, and token program account.
-     *
-     * @param owner               the public key of the owner
-     * @param mint                the public key of the mint
-     * @param tokenProgramAccount the public key of the token program account
-     * @return a new instance of {@link AssociatedTokenAddress}
-     */
-    public static AssociatedTokenAddress associatedTokenAddress(final PublicKey owner, final PublicKey mint, final PublicKey tokenProgramAccount)
-    {
-        return SolanaEncoding.deriveAssociatedTokenAddress(owner, mint, tokenProgramAccount);
-    }
-
     /**
      * Creates a new blockhash from the given byte array.
      *

src/main/java/com/lmax/solana4j/encoding/SolanaEncoding.java

@@ -2,7 +2,6 @@
 
 
 import com.lmax.solana4j.api.AddressLookupTable;
-import com.lmax.solana4j.api.AssociatedTokenAddress;
 import com.lmax.solana4j.api.Blockhash;
 import com.lmax.solana4j.api.Destination;
 import com.lmax.solana4j.api.InnerTransactionBuilder;
@@ -98,19 +97,6 @@ public static ProgramDerivedAddress deriveProgramAddress(final List<byte[]> seed
         return SolanaProgramDerivedAddress.deriveProgramAddress(seeds, programId);
     }
 
-    /**
-     * Derives an associated token address for the given owner, mint, and token program account.
-     *
-     * @param owner               the public key of the owner
-     * @param mint                the public key of the mint
-     * @param tokenProgramAccount the public key of the token program account
-     * @return a new instance of {@link AssociatedTokenAddress}
-     */
-    public static AssociatedTokenAddress deriveAssociatedTokenAddress(final PublicKey owner, final PublicKey mint, final PublicKey tokenProgramAccount)
-    {
-        return SolanaAssociatedTokenAddress.deriveAssociatedTokenAddress(owner, mint, tokenProgramAccount);
-    }
-
     /**
      * Creates a new blockhash from the given byte array.
      *

src/main/java/com/lmax/solana4j/programs/AssociatedTokenProgram.java

@@ -4,12 +4,15 @@
 import com.lmax.solana4j.api.ProgramDerivedAddress;
 import com.lmax.solana4j.api.PublicKey;
 import com.lmax.solana4j.api.TransactionBuilder;
+import com.lmax.solana4j.encoding.SolanaEncoding;
 import org.bitcoinj.core.Base58;
 
 import java.nio.ByteOrder;
+import java.util.List;
 
 import static com.lmax.solana4j.encoding.SysVar.RENT;
 import static com.lmax.solana4j.programs.SystemProgram.SYSTEM_PROGRAM_ACCOUNT;
+import static java.util.Objects.requireNonNull;
 
 /**
  * Program for managing associated token accounts on the Solana blockchain.
@@ -97,4 +100,25 @@ public AssociatedTokenProgram createAssociatedToken(
 
         return this;
     }
+
+    /**
+     * Derives a program address for a given owner, token program account, and mint.
+     * This method generates a program-derived address based on the combination of the owner's public key,
+     * the token program account's public key, and the mint's public key, using the associated token program account.
+     *
+     * @param owner the owner's public key; must not be null
+     * @param tokenProgramAccount the token program account's public key; must not be null
+     * @param mint the mint's public key; must not be null
+     * @return the derived program address based on the provided owner, token program account, and mint public keys
+     * @throws NullPointerException if the owner, tokenProgramAccount, or mint is null
+     */
+    public static ProgramDerivedAddress deriveAddress(final PublicKey owner, final PublicKey tokenProgramAccount, final PublicKey mint)
+    {
+        requireNonNull(owner, "The owner public key must be specified, but was null");
+        requireNonNull(tokenProgramAccount, "The token program public key must be specified, but was null");
+        requireNonNull(mint, "The mint public key must be specified, but was null");
+
+        return SolanaEncoding.deriveProgramAddress(List.of(owner.bytes(), tokenProgramAccount.bytes(), mint.bytes()), ASSOCIATED_TOKEN_PROGRAM_ACCOUNT);
+    }
+
 }

src/test-support/java/com/lmax/solana4j/SolanaNodeDsl.java

@@ -6,7 +6,6 @@
 import com.lmax.simpledsl.api.RepeatingGroup;
 import com.lmax.simpledsl.api.RequiredArg;
 import com.lmax.solana4j.api.AddressLookupTable;
-import com.lmax.solana4j.api.AssociatedTokenAddress;
 import com.lmax.solana4j.api.ProgramDerivedAddress;
 import com.lmax.solana4j.api.PublicKey;
 import com.lmax.solana4j.assertion.Condition;
@@ -17,6 +16,7 @@
 import com.lmax.solana4j.domain.TokenProgram;
 import com.lmax.solana4j.encoding.SolanaEncoding;
 import com.lmax.solana4j.programs.AddressLookupTableProgram;
+import com.lmax.solana4j.programs.AssociatedTokenProgram;
 import com.lmax.solana4j.programs.BpfLoaderUpgradeableProgram;
 import com.lmax.solana4j.programs.SystemProgram;
 import com.lmax.solana4j.solanaclient.api.AccountInfo;
@@ -36,7 +36,6 @@
 import static com.lmax.solana4j.assertion.Condition.isEqualTo;
 import static com.lmax.solana4j.assertion.Condition.isNotNull;
 import static com.lmax.solana4j.assertion.Condition.isTrue;
-import static com.lmax.solana4j.encoding.SolanaEncoding.deriveAssociatedTokenAddress;
 import static com.lmax.solana4j.programs.SystemProgram.MINT_ACCOUNT_LENGTH;
 import static com.lmax.solana4j.programs.SystemProgram.NONCE_ACCOUNT_LENGTH;
 import static com.lmax.solana4j.programs.TokenProgram.ACCOUNT_LAYOUT_SPAN;
@@ -581,7 +580,7 @@ public void createAssociatedTokenAccount(final String... args)
         final TokenProgram tokenProgram = TokenProgram.fromName(params.value("tokenProgram"));
         final TestPublicKey owner = testContext.data(TestDataType.TEST_PUBLIC_KEY).lookup(params.value("owner"));
 
-        final AssociatedTokenAddress associatedTokenAddress = deriveAssociatedTokenAddress(owner.getSolana4jPublicKey(), tokenMint.getSolana4jPublicKey(), tokenProgram.getProgram());
+        final ProgramDerivedAddress associatedTokenAddress = AssociatedTokenProgram.deriveAddress(owner.getSolana4jPublicKey(), tokenProgram.getProgram(), tokenMint.getSolana4jPublicKey());
         testContext.data(TestDataType.TEST_PUBLIC_KEY).store(params.value("associatedTokenAddress"), new TestPublicKey(associatedTokenAddress.address().bytes()));
 
         final TestKeyPair payer = testContext.data(TestDataType.TEST_KEY_PAIR).lookup(params.value("payer"));

src/test/java/com/lmax/solana4j/programs/AssociatedTokenProgramTest.java

@@ -0,0 +1,70 @@
+package com.lmax.solana4j.programs;
+
+import com.lmax.solana4j.Solana;
+import com.lmax.solana4j.api.ProgramDerivedAddress;
+import com.lmax.solana4j.api.PublicKey;
+import org.junit.jupiter.api.Test;
+
+import static com.lmax.solana4j.Solana4jTestHelper.ACCOUNT1;
+import static com.lmax.solana4j.Solana4jTestHelper.ACCOUNT2;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThatThrownBy;
+import static org.assertj.core.api.AssertionsForInterfaceTypes.assertThat;
+
+public class AssociatedTokenProgramTest
+{
+    @Test
+    void throwsOnNullOwnerKey()
+    {
+        assertThatThrownBy(() ->
+                AssociatedTokenProgram.deriveAddress(null, Solana.account(ACCOUNT1), Solana.account(ACCOUNT2)))
+                .isInstanceOf(NullPointerException.class);
+    }
+
+    @Test
+    void throwsOnNullMintKey()
+    {
+        assertThatThrownBy(() ->
+                AssociatedTokenProgram.deriveAddress(Solana.account(ACCOUNT1), null, Solana.account(ACCOUNT2)))
+                .isInstanceOf(NullPointerException.class);
+    }
+
+    @Test
+    void throwsOnNullTokenProgramKey()
+    {
+        assertThatThrownBy(() ->
+                AssociatedTokenProgram.deriveAddress(Solana.account(ACCOUNT1), null, Solana.account(ACCOUNT2)))
+                .isInstanceOf(NullPointerException.class);
+    }
+
+    @Test
+    void shouldCreateAssociatedTokenAddress()
+    {
+        final PublicKey owner = Solana.account(ACCOUNT1);
+        final PublicKey mint = Solana.account(ACCOUNT2);
+
+        final ProgramDerivedAddress associatedTokenAddress = AssociatedTokenProgram.deriveAddress(
+                owner,
+                TokenProgram.PROGRAM_ACCOUNT,
+                mint);
+
+        assertThat(associatedTokenAddress.programId()).isEqualTo(AssociatedTokenProgram.ASSOCIATED_TOKEN_PROGRAM_ACCOUNT);
+        assertThat(associatedTokenAddress.address().base58()).isEqualTo("BtHaGVQ4uRjgxGSoADNkPLxQUVBFhv3GaLbrU5jQnbmh");
+        assertThat(associatedTokenAddress.nonce()).isEqualTo(255);
+    }
+
+    @Test
+    void shouldCreateAssociatedToken2022Address()
+    {
+        final PublicKey owner = Solana.account(ACCOUNT1);
+        final PublicKey mint = Solana.account(ACCOUNT2);
+
+        final ProgramDerivedAddress associatedTokenAddress = AssociatedTokenProgram.deriveAddress(
+                owner,
+                Token2022Program.PROGRAM_ACCOUNT,
+                mint);
+
+        assertThat(associatedTokenAddress.programId()).isEqualTo(AssociatedTokenProgram.ASSOCIATED_TOKEN_PROGRAM_ACCOUNT);
+        assertThat(associatedTokenAddress.address().base58()).isEqualTo("6TZpgbVr5gCryZfwJEEgTjp88DU4LWDkVA68ACUdC9gK");
+        assertThat(associatedTokenAddress.nonce()).isEqualTo(253);
+    }
+}