Prerequisites

Install the required environment before using the SDK.

• JDK 8 or later
• Windows 10 or later (native library dependency)
• Place the ECR native library (.dll) in java.library.path

Note: Earlier versions of the Java SDK required a DLL dependency (java.library.path). The current release supports pure‑Java integration without DLLs.

• Use the DLL‑free approach for new projects.
• Use the DLL‑based approach only for backward compatibility.

For integration steps, refer to Java SDK Integration.

Library Import

Add the JNI wrapper and import the SDK classes.

import java.net.Socket;
import java.io.*;

Declare native methods for request packing and response parsing.

public static native int pack(String reqData, int txnType, String signature, byte[] buffer);
public static native int parse(byte[] response, byte[] fields);

Core Components

Use the SDK’s native functions to build and parse transaction data.

• pack() – Format request data into a buffer.
• parse() – Extract response fields from terminal output.
• Socket – Establish TCP/IP connection with the terminal.

Configuration Persistence

• The SDK uses java.library.path to locate the native .dll.
• Connection parameters (IP, port) are defined at runtime in the client code.
• No external JSON configuration file is required.

Runtime Behaviors

• The SDK manages communication through socket connections.
• Establish TCP/IP session with the terminal.
• Send packed request data using pack().
• Receive terminal response and parse with parse().
• Close the socket after transaction completion.

Transaction Flow

Initialize SDK → Configure POS → Connect Device → Pack Request → Execute Transaction → Receive Response → Parse Response