| --- |
| title: Messages |
| description: Messages |
| weight: 2 |
| tags: ['kafka', 'docs'] |
| aliases: |
| keywords: |
| type: docs |
| --- |
| |
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| Messages consist of a variable-length header, a variable-length opaque key byte array and a variable-length opaque value byte array. The format of the header is described in the following section. Leaving the key and value opaque is the right decision: there is a great deal of progress being made on serialization libraries right now, and any particular choice is unlikely to be right for all uses. Needless to say a particular application using Kafka would likely mandate a particular serialization type as part of its usage. The `RecordBatch` interface is simply an iterator over messages with specialized methods for bulk reading and writing to an NIO `Channel`. |
