Create direct and non-direct ByteBuffer

In this example we are going to demonstrate several methods of creating a direct (memory-mapped) and non-direct ByteBuffer in Java.

Given a direct byte buffer, the Java virtual machine will make a best effort to perform native I/O operations directly upon it. That is, it will attempt to avoid copying the buffer’s content to (or from) an intermediate buffer before (or after) each invocation of one of the underlying operating system’s native I/O operations.

// Create a byte array
byte[] bytes = new byte[10];

// Wrap a byte array into a buffer
ByteBuffer buf = ByteBuffer.wrap(bytes);

// Allocate a new non-direct byte buffer with a 10 byte capacity
// The underlying storage is a byte array.
buf = ByteBuffer.allocate(10);

// Allocatea new direct (memory-mapped) byte buffe with a 10 byte capacity
buf = ByteBuffer.allocateDirect(10);

This was an example of how to create direct and non-direct ByteBuffer in Java.

Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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