查看编译class文件时，使用的JDK版本（只能查看到大版本）

■本地JDK

 

■查看方式1

以十六进行形式打开文件

format-hex ./HelloWorld.class

 

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CA FE BA BE 00 00 00 34 00 1D 0A 00 06 00 0F 09

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HEX	十进制	jdk
2E	46	jdk1.2
2F	47	jdk1.3
30	48	jdk1.4
31	49	jdk1.5
32	50	jdk1.6
33	51	jdk1.7
34	52	jdk1.8
35	53	jdk9
36	54	jdk10
37	55	jdk11
38	56	jdk12
39	57	jdk13

 

■查看方式2

javap -v XXX.class

javap -v HelloWorld.class

major 显示为52 （是十进制）

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PS C:\test\myJava> javap -v HelloWorld.class                                                                            Classfile /C:/test/myJava/HelloWorld.class
  Last modified 2018-11-18; size 430 bytes
  MD5 checksum 19f3d94a06c6349d050673c6dabd9616
  Compiled from "HelloWorld.java"
class HelloWorld
  minor version: 0
  major version: 52
  flags: ACC_SUPER
Constant pool:
   #1 = Methodref          #6.#15         // java/lang/Object."":()V
   #2 = Fieldref           #16.#17        // java/lang/System.out:Ljava/io/PrintStream;

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