java - 如何修复 UnsupportedClassVersionError？

Question

这个问题已经有答案了:

Exception in thread "main" java.lang.UnsupportedClassVersionError: a (Unsupported major.minor version 51.0) [duplicate] (5 个回答)

已关闭 3 年前。

Exception in thread "main" java.lang.UnsupportedClassVersionError:
/DataManager has been compiled by a more recent version of the Java 
Runtime (class file version 56.0), this version of the Java Runtime
recognizes class file versions up to 52.0

这是堆栈跟踪:

Stacktrace:] with root causejava.lang.UnsupportedClassVersionError: com/north/webapp/DataManager has been compiled by a more recent version of the Java Runtime (class file version 56.0), this version of the Java Runtime only recognizes class file versions up to 52.0 (unable to load class [com.north.webapp.DataManager])    at org.apache.catalina.loader.WebappClassLoaderBase.findClassInternal(WebappClassLoaderBase.java:2424)    at org.apache.catalina.loader.WebappClassLoaderBase.findClass(WebappClassLoaderBase.java:865)    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1334)    at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1188)    at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:122)    at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java:59)    at org.apache.jsp.index_jsp._jspService(index_jsp.java:130)    at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)    at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:476)    at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)    at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)    at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)    at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:678)    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:860)    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1587)    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)    at java.lang.Thread.run(Thread.java:748)

由于尝试编译时遇到错误，我已将 jdk 从版本 9 更改为 8

Answer 1

版本 56 的类文件在 java12 或更高版本上运行。您正在使用 java 1.8。

如果生成此类文件的源文件在您的控制范围内，您可以尝试使用 java.lang.Class 文件重新编译它。否则，您必须至少升级到 java12 才能运行它。