What are the methods of implementing zero copy in Java?

1. Utilize the ByteBuffer class from the Java NIO (New Input/Output) library to achieve zero copy. This class can manipulate heap memory or direct memory, facilitating zero copy data transfers within memory.
2. Utilize the transferTo() or transferFrom() methods of the FileChannel class in Java NIO to achieve zero-copy. These methods allow for direct transfer of data from one channel to another without the need for an intermediary buffer.
3. Implement zero copy using the MappedByteBuffer class in Java NIO. This class can map a file directly into memory, allowing for reading and writing operations to be done directly in memory, achieving zero copy.
4. Implement zero-copy using the DirectByteBuffer class in Java NIO. It is a direct memory buffer that allows direct access to native memory through JNI (Java Native Interface) to achieve zero-copy.

These methods can all help reduce or eliminate the need for data to be copied in memory during data transmission, thereby enhancing the efficiency and performance of data transfer.