C struct to Java

I have an USB device with firmware written in C language. This device will exchange data structures with Android app written in Java. Now the structures are declared in C. What is the best way to handle them in Java.

Currently, I have this in C:

// In report - data from USB device to Java
typedef struct {
   uint8 Cmd;
   union {
      TSomeStruct Something;
      uint32 Value;
   };
} __packed TInReport;

// Out report - data from Java to USB device
typedef struct {
   uint8 Cmd;
   union {
      int32 Status;
      uint16 Id;
   };
} __packed TOutReport;

I can rewrite these declaration in Java. Then, is there a simple way Java can decode received bytes to its native object and encode its native object to bytes (with correctly aligned members)?