How to check Java version from compiled classes
javap -cp target/classes -verbose com.zemian.hellojava.App | grep 'major version'
major version: 49
You may use this forumla to get the JDK version:
<class_file_major_ver> - 44 = JDK version. So this means above class
is targeted for JDK 5 (1.5).
Here are more examples of different class format versions matching to JDK versions.
major version: 45.3 = Java 1.1
major version: 46 = Java 1.2
major version: 47 = Java 1.3
major version: 48 = Java 1.4
major version: 49 = Java 1.5
major version: 50 = Java 1.6
major version: 51 = Java 1.7
major version: 52 = Java 1.8
major version: 53 = Java 9
major version: 54 = Java 10
Ref: https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-4.html
