Tomcat 不识别 Java 升级

Question

I recently upgraded the Java Version from 11 to 17. But whenever I run the.war file I get the following error:

java.lang.UnsupportedClassVersionError: somePackage/SomeClass has been compiled by a more recent version of the Java Runtime (class file version 61.0), this version of the Java Runtime only recognizes class file versions up to 55.0 (unable to load class [somePackage.SomeClass])

To verify if the Tomcat is using the right version, I did this:

[root@ip-172-31-21-71 apache-tomcat-9.0.58]# java -cp lib/catalina.jar org.apache.catalina.util.ServerInfo
Server version: Apache Tomcat/9.0.58
Server built:   Jan 15 2022 14:37:38 UTC
Server number:  9.0.58.0
OS Name:        Linux
OS Version:     4.14.214-160.339.amzn2.x86_64
Architecture:   amd64
JVM Version:    17.0.5+8-LTS
JVM Vendor:     Amazon.com Inc.
[root@ip-172-31-21-71 apache-tomcat-9.0.58]# ps -ef | grep tomcat
root     12088 11400  0 08:49 pts/0    00:00:00 grep --color=auto tomcat
root     15642     1  1 Nov16 ?        00:12:09 /opt/jdk-17.0.5/bin/java -Djava.util.logging.config.file=/opt/apache-tomcat-9.0.58/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Dfile.encoding=UTF-8 -Xms128m -Xmx700m -Djdk.tls.ephemeralDHKeySize=2048 -Djava.protocol.handler.pkgs=org.apache.catalina.webresources -Dorg.apache.catalina.security.SecurityListener.UMASK=0027 -Dignore.endorsed.dirs= -classpath /opt/apache-tomcat-9.0.58/bin/bootstrap.jar:/opt/apache-tomcat-9.0.58/bin/tomcat-juli.jar -Dcatalina.base=/opt/apache-tomcat-9.0.58 -Dcatalina.home=/opt/apache-tomcat-9.0.58 -Djava.io.tmpdir=/opt/apache-tomcat-9.0.58/temp org.apache.catalina.startup.Bootstrap start
[root@ip-172-31-21-71 apache-tomcat-9.0.58]# /opt/jdk-17.0.5/bin/java --version
java 17.0.5 2022-10-18 LTS
Java(TM) SE Runtime Environment (build 17.0.5+9-LTS-191)
Java HotSpot(TM) 64-Bit Server VM (build 17.0.5+9-LTS-191, mixed mode, sharing)

Even ${JAVA_HOME} points to the right directory. Everything works well locally. I don't know what I'm missing. Any suggestions would be appreciated. Thanks in advance.

Answer 1

Well... since you are running startup.sh by hand...

The startup.sh calls catalina.sh start . And the catalina.sh script uses the JRE_HOME or JAVA_HOME environment variables. But it loads them by sourcing the setenv.sh script if it can find them.

So my bet is that your setenv.sh is where the salient JRE_HOME or JAVA_HOME settings are.

But the good news is that all of these files are just shell scripts, so you can read them to figure out what it going on. And if you can't read shell scripts, you can add set -x in the respective scripts to watch what they are doing!

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By the way:

To verify if the Tomcat is using the right version, I did this: $ java -cp lib/catalina.jar org.apache.catalina.util.ServerInfo

That is not a valid test. You have to figure out how the scripts are choosing the JRE that they are using.