Add ability to deserialize both account indexes and account addresses…

… from the same "account" field in the json (the fact you have to do this is just bad api design in my opinion)

client/src/integration-test/java/com/lmax/solana4j/client/jsonrpc/GetTransactionContractTest.java

@@ -112,9 +112,10 @@ void shouldGetTransactionJsonEncodingOptionalParam() throws SolanaJsonRpcClientE
 
         final var instruction = message.getInstructions().get(0);
         assertThat(instruction.getData()).isEqualTo("3Bxs3zzLZLuLQEYX");
-        assertThat(instruction.getAccounts()).hasSize(2);
-        assertThat(instruction.getAccounts().get(0)).isEqualTo(0);
-        assertThat(instruction.getAccounts().get(1)).isEqualTo(1);
+        assertThat(instruction.getAccounts().getIndexes()).hasSize(2);
+        assertThat(instruction.getAccounts().getAddresses()).isNull();
+        assertThat(instruction.getAccounts().getIndexes().get(0)).isEqualTo(0);
+        assertThat(instruction.getAccounts().getIndexes().get(1)).isEqualTo(1);
         assertThat(instruction.getProgramIdIndex()).isEqualTo(2);
         assertThat(instruction.getStackHeight()).isEqualTo(null);
 
@@ -164,6 +165,7 @@ void shouldGetTransactionJsonParsedEncodingOptionalParam() throws SolanaJsonRpcC
 
         // would have been present if encoding json not jsonParsed
         assertThat(instruction.getData()).isNull();
+        // jsonParsed so getAccounts().getIndexes() is null (as expected) but i _would_ expect getAccounts().getAddresses() to NOT be null ...
         assertThat(instruction.getAccounts()).isNull();
         assertThat(instruction.getProgramIdIndex()).isNull();
         assertThat(instruction.getStackHeight()).isEqualTo(null);

client/src/main/java/com/lmax/solana4j/client/api/TransactionResponse.java

@@ -490,6 +490,31 @@ interface Header
         }
     }
 
+    /**
+     * Represents an inner instruction in a Solana transaction.
+     * Inner instructions are instructions that are executed within a broader transaction and can involve program invocations.
+     * This interface provides access to the index of the inner instruction and the list of associated instructions.
+     */
+    interface InnerInstruction
+    {
+
+        /**
+         * Returns the index of the inner instruction within the transaction.
+         * The index indicates the position of this inner instruction in the list of instructions in the transaction.
+         *
+         * @return the index of the inner instruction
+         */
+        long getIndex();
+
+        /**
+         * Returns the list of instructions that are part of this inner instruction.
+         * Each instruction represents an action or a program invocation that is part of the inner transaction.
+         *
+         * @return a list of {@link Instruction} objects representing the inner instructions
+         */
+        List<Instruction> getInstructions();
+    }
+
     /**
      * Represents an instruction in a Solana transaction.
      * Instructions define actions to be executed on the Solana blockchain, specifying accounts involved,
@@ -499,12 +524,15 @@ interface Header
     interface Instruction
     {
         /**
-         * Returns a list of account indices involved in the instruction.
-         * Each index refers to an account in the transaction's account list that is affected by this instruction.
+         * Retrieves information about the accounts involved in this instruction.
+         * Each account is referenced by its index within the transaction's account list
+         * and is associated with its corresponding Solana address.
          *
-         * @return a list of integers representing account indices
+         * @return an {@link InstructionAccounts} instance containing the index and address
+         *         of the affected account.
          */
-        List<Integer> getAccounts();
+        InstructionAccounts getAccounts();
+
 
         /**
          * Returns the base58-encoded data associated with the instruction.
@@ -563,31 +591,30 @@ interface Instruction
          * @return the stack height as an {@link Integer}, or null if not specified
          */
         Integer getStackHeight();
-    }
-
-
-    /**
-     * Represents an inner instruction in a Solana transaction.
-     * Inner instructions are instructions that are executed within a broader transaction and can involve program invocations.
-     * This interface provides access to the index of the inner instruction and the list of associated instructions.
-     */
-    interface InnerInstruction
-    {
 
         /**
-         * Returns the index of the inner instruction within the transaction.
-         * The index indicates the position of this inner instruction in the list of instructions in the transaction.
-         *
-         * @return the index of the inner instruction
+         * Represents an account involved in an instruction within a Solana transaction.
+         * This interface provides access to both the account index within the transaction's
+         * account list and its corresponding address.
          */
-        long getIndex();
+        interface InstructionAccounts
+        {
+            /**
+             * Retrieves the index of the account within the transaction's account list.
+             * This index is used to reference the account in the transaction's account array.
+             *
+             * @return the zero-based index of the account in the transaction's account list.
+             */
+            List<Integer> getIndexes();
+
+            /**
+             * Retrieves the address of the account involved in the instruction.
+             * This is a Base58-encoded string representing the Solana account.
+             *
+             * @return the Solana account address as a string.
+             */
+            List<String> getAddresses();
+        }
 
-        /**
-         * Returns the list of instructions that are part of this inner instruction.
-         * Each instruction represents an action or a program invocation that is part of the inner transaction.
-         *
-         * @return a list of {@link Instruction} objects representing the inner instructions
-         */
-        List<Instruction> getInstructions();
     }
 }

client/src/main/java/com/lmax/solana4j/client/jsonrpc/TransactionResponseDTO.java

@@ -691,7 +691,7 @@ public String toString()
 
         static final class InstructionDTO implements Instruction
         {
-            private final List<Integer> accounts;
+            private final InstructionAccountsDTO accounts;
             private final Map<String, Object> instructionParsed;
             private final String data;
             private final String program;
@@ -701,7 +701,7 @@ static final class InstructionDTO implements Instruction
 
             @JsonCreator
             InstructionDTO(
-                    final @JsonProperty("accounts") List<Integer> accounts,
+                    final @JsonProperty("accounts") InstructionAccountsDTO accounts,
                     final @JsonProperty("parsed") Map<String, Object> instructionParsed,
                     final @JsonProperty("data") String data,
                     final @JsonProperty("program") String program,
@@ -719,7 +719,7 @@ static final class InstructionDTO implements Instruction
             }
 
             @Override
-            public List<Integer> getAccounts()
+            public InstructionAccounts getAccounts()
             {
                 return accounts;
             }
@@ -774,6 +774,59 @@ public String toString()
                         '}';
             }
         }
+
+
+        @JsonDeserialize(using = InstructionAccountsDTO.InstructionAccountsDeserializer.class)
+        static final class InstructionAccountsDTO implements Instruction.InstructionAccounts
+        {
+            private final List<Integer> indexes;
+            private final List<String> addresses;
+
+            InstructionAccountsDTO(final List<Integer> indexes, final List<String> addresses)
+            {
+                this.indexes = indexes;
+                this.addresses = addresses;
+            }
+
+            @Override
+            public List<Integer> getIndexes()
+            {
+                return indexes;
+            }
+
+            @Override
+            public List<String> getAddresses()
+            {
+                return addresses;
+            }
+
+            static class InstructionAccountsDeserializer extends JsonDeserializer<InstructionAccountsDTO>
+            {
+                @Override
+                public InstructionAccountsDTO deserialize(final JsonParser parser, final DeserializationContext context) throws IOException
+                {
+                    final ObjectMapper mapper = (ObjectMapper) parser.getCodec();
+                    final JsonNode node = mapper.readTree(parser);
+
+                    if (node.isArray())
+                    {
+                        if (!node.isEmpty() && node.get(0).isTextual())
+                        {
+                            final List<String> addresses = mapper.convertValue(node, mapper.getTypeFactory().constructCollectionType(List.class, String.class));
+                            return new InstructionAccountsDTO(null, addresses);
+                        }
+                        else
+                        {
+                            final List<Integer> indexes = mapper.convertValue(node, mapper.getTypeFactory().constructCollectionType(List.class, Integer.class));
+                            return new InstructionAccountsDTO(indexes, null);
+                        }
+                    }
+
+                    throw new IOException("Unable to deserialize instruction accounts.");
+                }
+            }
+        }
+
     }
 
     static final class LoadedAddressesDTO implements TransactionMetadata.LoadedAddresses