Thursday, February 28, 2013

Find Java Class version

The command javap is used to find out information about the class including the major and minor version number however to quickly determine in Linux and OSX the java class version (the JDK version used to compile it) just use the file command. Here is a JDK6 compiled class in OSX
$ file MyClass.class
MyClass.class: compiled Java class data, version 50.0 (Java 1.6)
Here is a JDK7 compiled class on Linux:
$ file MyClass.class
MyClass.class: compiled Java class data, version 51.0
As a reminder here are the available versions as of today:
major  minor Java platform version 
45       3           1.0
45       3           1.1
46       0           1.2
47       0           1.3
48       0           1.4
49       0           1.5
50       0           1.6
51       0           1.7

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