[JAVA] What to do if ClassNotFoundException occurs when starting Tomcat

--Environment - CentOS Linux release 7.6.1810 (Core) - Eclipse 2019-03 (4.11.0) - Java1.6.0_41 - Apache Maven 3.2.5

Event: I got angry when I started tomcat in Eclipse

[Consol]Tab log

information: Initializing Spring root WebApplicationContext
2020-04-17 10:32:34.216 ERROR                                   Jotm.<init>:144 - Instanciation of TransactionFactory failed
java.rmi.StubNotFoundException: Stub class not found: org.objectweb.jotm.TransactionFactoryImpl_Stub; nested exception is: 
    java.lang.ClassNotFoundException: org.objectweb.jotm.TransactionFactoryImpl_Stub
...abridgement...
    at org.objectweb.jotm.Jotm.<init>(Jotm.java:140) ~[jotm-2.0.10.jar:"2.0.9"]
    at org.springframework.transaction.jta.JotmFactoryBean.<init>(JotmFactoryBean.java:95) ~[spring-dao-2.0.8.jar:2.0.8]
...abridgement...
Caused by: java.lang.ClassNotFoundException: org.objectweb.jotm.TransactionFactoryImpl_Stub
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1698) ~[catalina.jar:6.0.53]
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1544) ~[catalina.jar:6.0.53]
    at java.lang.Class.forName0(Native Method) ~[na:1.6.0_41]
    at java.lang.Class.forName(Class.java:274) ~[na:1.6.0_41]
    at sun.rmi.server.Util.createStub(Util.java:286) ~[na:1.6.0_41]
    ... 85 common frames omitted

Although it is displayed as jotm-2.0.10.jar in the log, I was wondering because it is jotm-2.1.1.pom defined in pom.xml of the project.

Project pom.xml

<dependency>
  <groupId>org.ow2.jotm</groupId>
  <artifactId>jotm</artifactId>
  <version>2.1.1</version>
  <type>pom</type>
  <exclusions>
...abridgement...
</dependency>
...abridgement...
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-dao</artifactId>
    <version>2.0.8</version>
</dependency>
...abridgement...

There is spring-dao-2.0.8.jar under jotm-2.0.10.jar in the log, so when I look at spring-dao-2.0.8.pom, it says" Yes! "

bash:spring-dao-2.0.8.Take a look at pom

$ cat ~/.m2/repository/org/springframework/2.0.8/spring-dao-2.0.8.pom
...abridgement...
<dependency>
  <groupId>jotm</groupId>
  <artifactId>jotm</artifactId>
  <version>2.0.10</version>
  <optional>true</optional>
</dependency>
...abridgement...

Cause: There is no class beyond the jar dependency defined in the project's pom.xml

Used by spring-dao-2.0.8.pom Used by jotm-2.0.10.jar ʻorg.objectweb.jotm.TransactionFactoryImpl_Stub` is missing

Workaround: Define a jar in pom.xml that contains the class at the end of the dependency

1. Use JAR Search --findJAR.com to find out what jar contains ʻorg.objectweb.jotm.TransactionFactoryImpl_Stub`.
2. Search Maven Repository: Search / Browse / Explore for jotm-jrmp-stubs found by the search.
3. Add the definition to the project's pom.xml

Project pom.xml

...abridgement...
<dependency>
    <groupId>jotm</groupId>
    <artifactId>jotm_jrmp_stubs</artifactId>
    <version>2.0.10</version>
</dependency>
...abridgement...