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Additionally, dropping Java 7 will allow us to support the impending Java 9 without making our testing matrix even more complex (this is particularly useful for system tests that take hours to run). It will also make it easier to support Scala 2.12 properly (since it requires Java 8, we don't currently build with Scala 2.12 by default as it requires Java 8).

Many other open-source projects have taken the leap already. Examples are Cassandra, Lucene, Akka, Hadoop 3, Jetty, Guava, Eclipse, IntelliJ, Jenkins and many others. Even Android will support Java 8 in the next version (although it will take a while before
most phones will use that version sadly). This reduces (but does not eliminate) the chance that we would be the first project that would cause a user to consider a Java upgrade.

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Users who cannot upgrade to Java 8 can continue to use Kafka 0.10.x until they can upgrade. 0.11.x brokers will support 0.10.x clients and 0.11.x clients will support 0.10.x brokers, so upgrades can be incremental (while keeping the older message format until enough clients have been upgraded). This is useful if some clients are stuck in Java 7, for example.

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