What version of Java does Cassandra 3 require

Question

The recommended version of Java for Cassandra 2.0 was Java 7. But which version is recommended or required for Cassandra 3 (specifically, version 3.5)?

Some information suggests that Java 7 or Java 8 are required; that is, that Java 7 is still OK:

The Cassandra Wiki says:

Cassandra requires the most stable version of Java 7 or 8

The change log for Cassandra 3.5 does not mention changing the required JRE. It does have a change (CASSANDRA-7028) to "Allow compilation in java 8". But allow is not the same as require.

I am answering my own question, as is encouraged. – Raedwald May 18 '16 at 10:47 — Raedwald, May 18 '16 at 10:47

score 8 · Accepted Answer · edited May 23 '17 at 10:34

8

Cassandra 3.0+ requires Java 8.

The cassandra-env.sh script, used by the cassandra shell script, examines the JVM version and refuses to run if the JVM version is before 1.8.
If you try to run code directly using one of the classes of the cassandra-all.jar using a Java 7 environment you will get a java.lang.UnsupportedClassVersionError complaining of Unsupported major.minor version 52.0.
The META-INF/MANIFEST.MF file in the JAR indicates it was compiled using a Java 8 compiler: Created-By: 1.8.0_45-b14 (Oracle Corporation).
The Datastax announcement about Cassandra 3 says that it requires Java 8.

In conclusion, the Cassandra Wiki is wrong and the Cassandra change log is misleading.

edited May 23 '17 at 10:34

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answered May 18 '16 at 10:47

Raedwald

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I've updated the Wiki, thanks for pointing that out. Instead of the changelog, you should be looking at NEWS.txt, specifically the "Upgrading" section for your version (and any versions you may skip). For 3.0, this says "3.0 requires Java 8u40 or later.". – Tyler Hobbs May 18 '16 at 21:07
You'll run into a similiar issue with JDK 10 since they changed the naming scheme -- the cassandra-env.sh script's parsing is naively assuming the old naming convention. – Roddy of the Frozen Peas May 16 '18 at 01:15

What version of Java does Cassandra 3 require

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