【问题记录】How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version

我不是女神ヾ 2022-06-03 07:42 97阅读 0赞

# 来源：https://stackoverflow.com/questions/10382929/how-to-fix-java-lang-unsupportedclassversionerror-unsupported-major-minor-versi #

今天出现报错：nested exception is java.lang.UnsupportedClassVersionError: com/google/commo。 搜索后在Stack Overflow找到解决方法，跳转java版本

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   <td style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:top"> 
    <div style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline"> 
     <div style="margin:0px 0px 5px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:15px; line-height:1.3; font-family:inherit; vertical-align:baseline; width:660px; word-wrap:break-word"> 
      <p style="margin-top:0px; margin-bottom:1em; padding-top:0px; padding-bottom:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; clear:both"> I am trying to use&nbsp;<a href="http://en.wikipedia.org/wiki/Notepad%2B%2B" style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; color:rgb(0,89,153)" rel="nofollow">Notepad++</a>&nbsp;as my all-in-one tool edit, run, compile, etc.</p> 
      <p style="margin-top:0px; margin-bottom:1em; padding-top:0px; padding-bottom:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; clear:both"> I have&nbsp;<a href="http://en.wikipedia.org/wiki/Java_Virtual_Machine#Execution_environment" style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; color:rgb(0,89,153)" rel="nofollow">JRE</a>&nbsp;installed, and I have setup my path variable to the .../bin directory.</p> 
      <p style="margin-top:0px; margin-bottom:1em; padding-top:0px; padding-bottom:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; clear:both"> When I run my "Hello world" in Notepad++, I get this message:</p> 
      <pre style="margin-top:0px; margin-bottom:1em; padding:5px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:13px; line-height:inherit; font-family:Consolas,Menlo,Monaco,&quot;Lucida Console&quot;,&quot;Liberation Mono&quot;,&quot;DejaVu Sans Mono&quot;,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,monospace,sans-serif; vertical-align:baseline; width:auto; max-height:600px; overflow:auto; background-color:rgb(239,240,241); word-wrap:normal"><code style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; line-height:inherit; font-family:Consolas,Menlo,Monaco,&quot;Lucida Console&quot;,&quot;Liberation Mono&quot;,&quot;DejaVu Sans Mono&quot;,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,monospace,sans-serif; vertical-align:baseline; white-space:inherit">java.lang.UnsupportedClassVersionError: test_hello_world :
 Unsupported major.minor version 51.0
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClassCond(Unknown Source)
       .........................................
</code></pre> 
      <p style="margin-top:0px; margin-bottom:1em; padding-top:0px; padding-bottom:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; clear:both"> I think the problem here is about versions; some version of Java may be old or too new.</p> 
      <ol style="margin:0px 0px 1em 30px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; list-style-position:initial"> 
       <li style="margin:0px 0px 0.5em; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; word-wrap:break-word"> How do I fix it?</li> 
       <li style="margin:0px 0px 0.5em; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; word-wrap:break-word"> Should I install the JDK, and setup my path variable to the JDK instead of JRE?</li> 
       <li style="margin:0px; padding:0px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:undefined; line-height:inherit; font-family:inherit; vertical-align:baseline; word-wrap:break-word"> What is the difference between the&nbsp;<code style="margin:0px; padding:1px 5px; border:0px; font-style:inherit; font-variant:inherit; font-weight:inherit; font-size:13px; line-height:inherit; font-family:Consolas,Menlo,Monaco,&quot;Lucida Console&quot;,&quot;Liberation Mono&quot;,&quot;DejaVu Sans Mono&quot;,&quot;Bitstream Vera Sans Mono&quot;,&quot;Courier New&quot;,monospace,sans-serif; vertical-align:baseline; background-color:rgb(239,240,241); white-space:pre-wrap">PATH</code>&nbsp;variable in JRE or JDK?</li> 
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解答：

he version number shown describes the version of the JRE the class file is compatible with.

The reported major numbers are:

Java SE 9 = 53,
    Java SE 8 = 52,
    Java SE 7 = 51,
    Java SE 6.0 = 50,
    Java SE 5.0 = 49,
    JDK 1.4 = 48,
    JDK 1.3 = 47,
    JDK 1.2 = 46,
    JDK 1.1 = 45

(Source: [Wikipedia][])

To fix the actual problem you should try to either run the Java code with a newer version of Java JRE or specify the target parameter to the Java compiler to instruct the compiler to create code compatible with earlier Java versions.

For example, in order to generate class files compatible with Java 1.4, use the following command line:

javac -target 1.4 HelloWorld.java

With newer versions of the Java compiler you are likely to get a warning about the bootstrap class path not being set. More information about this error is available in blog post [New javac warning for setting an older source without bootclasspath][].

[Wikipedia]: https://en.wikipedia.org/wiki/Java_class_file#General_layout
[New javac warning for setting an older source without bootclasspath]: https://blogs.oracle.com/darcy/entry/bootclasspath_older_source