Is my Java version 5?

I have a program whose README says it requires Java 5 or higher. I check the versio开发者_运维知识库n of Java on my Ubuntu:

$ java -version
java version "1.6.0_20"
OpenJDK Runtime Environment (IcedTea6 1.9.9) (6b20-1.9.9-0ubuntu1~10.10.2)
OpenJDK Server VM (build 19.0-b09, mixed mode)

I was wondering if 1.6.0_20 means Java 1.6.0_20, and therefore far older than Java 5? Thanks and regards!

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Java version numbers are weird. In some contexts they include an initial 1.; others do not. But 1.6.0 is what people usually call "Java 6", so you should be okay here.

Back in the day, there was "Java 1.1", which had a version number of 1.1.x. However, when "Java2" was released it had a version number of 1.2.x, and it's been like that ever since.

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Java 1.6.x is Java 6.

See here: http://en.wikipedia.org/wiki/Java_version_history#Java_SE_6_.28December_11.2C_2006.29

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You've actually got Java 6 so you should be ok!

Java 1.5.x is Java 5; Java 1.6.x is Java 6.