Added protocol

src/main/java/Main/ProtocolMessage.java

@@ -0,0 +1,23 @@
+package Main;
+
+public class ProtocolMessage {
+    int length;
+    char[] message;
+
+    /** Convert an integer into 4-byte array */
+    private byte[] intToByte(int value) {
+        return new byte[] {
+                (byte)(value >>> 24),
+                (byte)(value >>> 16),
+                (byte)(value >>> 8),
+                (byte)value};
+    }
+
+    /** Convert a byte array into 4-byte integer */
+    private int byteToInt(byte[] bytes) {
+        return bytes[0] << 24 |
+                (bytes[1] & 0xFF) << 16 |
+                (bytes[2] & 0xFF) << 8 |
+                (bytes[3] & 0xFF);
+    }
+}