javap命令查看jar包class编译版本，javapjar

javap命令查看jar包class编译版本，javapjar

版本对照如下：

Java 1.2 uses major version 46

Java 1.3 uses major version 47

Java 1.4 uses major version 48

Java 5 uses major version 49

Java 6 uses major version 50

Java 7 uses major version 51

Java 8 uses major version 52

Java 9 uses major version 53

使用如下命令查看：

[root@localhost]# javap -classpath test.jar test/Main -verbose 2>&1 | grep major
  major version: 51