title: Spring Boot with non-embedded Tomcat: loader constraint violation error
body: <p>I have an error when trying to display a JSP with Spring Boot. Here is my configuration:</p>
  
  <ul>
  <li>Spring source STS (last version)</li>
  <li>Spring Boot 1.1.8 (last release to date)</li>
  <li>Java 1.7</li>
  <li>Tomcat 8.0.14 (I'm not using the embedded tomcat, so I launch manually with the spring boot application added)</li>
  </ul>
  
  <p>My JSP file is barebones:</p>
  
  <pre><code>TEST
  </code></pre>
  
  <p>Here is my pom.xml : </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"&gt;
  &lt;modelVersion&gt;4.0.0&lt;/modelVersion&gt;
  
  &lt;groupId&gt;com.edhec&lt;/groupId&gt;
  &lt;artifactId&gt;stdapps&lt;/artifactId&gt;
  &lt;version&gt;0.0.1-SNAPSHOT&lt;/version&gt;
  &lt;packaging&gt;war&lt;/packaging&gt;
  
  &lt;name&gt;stdapps&lt;/name&gt;
  &lt;description&gt;Project stdapps&lt;/description&gt;
  
  &lt;parent&gt;
      &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
      &lt;artifactId&gt;spring-boot-starter-parent&lt;/artifactId&gt;
      &lt;version&gt;1.1.8.RELEASE&lt;/version&gt;
      &lt;relativePath/&gt; &lt;!-- lookup parent from repository --&gt;
  &lt;/parent&gt;
  
  &lt;dependencies&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-data-jpa&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-web&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-security&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-data-rest&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-websocket&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-tomcat&lt;/artifactId&gt;
          &lt;scope&gt;provided&lt;/scope&gt;
      &lt;/dependency&gt;
  
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
          &lt;artifactId&gt;spring-boot-starter-test&lt;/artifactId&gt;
          &lt;scope&gt;test&lt;/scope&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.hibernate&lt;/groupId&gt;
          &lt;artifactId&gt;hibernate-c3p0&lt;/artifactId&gt;
          &lt;version&gt;4.3.6.Final&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;com.oracle&lt;/groupId&gt;
          &lt;artifactId&gt;ojdbc14&lt;/artifactId&gt;
          &lt;version&gt;10.2.0.4.0&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;!-- CAS Client --&gt;
      &lt;dependency&gt;
         &lt;groupId&gt;org.jasig.cas.client&lt;/groupId&gt;
         &lt;artifactId&gt;cas-client-core&lt;/artifactId&gt;
         &lt;version&gt;3.3.3&lt;/version&gt;
         &lt;scope&gt;runtime&lt;/scope&gt;
         &lt;type&gt;jar&lt;/type&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.security&lt;/groupId&gt;
          &lt;artifactId&gt;spring-security-cas&lt;/artifactId&gt;
          &lt;type&gt;jar&lt;/type&gt;
          &lt;scope&gt;compile&lt;/scope&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.springframework.security&lt;/groupId&gt;
          &lt;artifactId&gt;spring-security-taglibs&lt;/artifactId&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;commons-beanutils&lt;/groupId&gt;
          &lt;artifactId&gt;commons-beanutils&lt;/artifactId&gt;
          &lt;version&gt;1.9.2&lt;/version&gt;
      &lt;/dependency&gt;
      &lt;dependency&gt;
          &lt;groupId&gt;org.apache.commons&lt;/groupId&gt;
          &lt;artifactId&gt;commons-lang3&lt;/artifactId&gt;
          &lt;version&gt;3.3.2&lt;/version&gt;
      &lt;/dependency&gt;
  
  &lt;/dependencies&gt;
  
  &lt;properties&gt;
      &lt;project.build.sourceEncoding&gt;UTF-8&lt;/project.build.sourceEncoding&gt;
      &lt;start-class&gt;com.edhec.stdapps.Application&lt;/start-class&gt;
      &lt;java.version&gt;1.7&lt;/java.version&gt;
      &lt;tomcat.version&gt;8.0.14&lt;/tomcat.version&gt;
  &lt;/properties&gt;
  
  &lt;build&gt;
      &lt;plugins&gt;
          &lt;plugin&gt;
              &lt;groupId&gt;org.springframework.boot&lt;/groupId&gt;
              &lt;artifactId&gt;spring-boot-maven-plugin&lt;/artifactId&gt;
          &lt;/plugin&gt;
      &lt;/plugins&gt;
  &lt;/build&gt;
  </code></pre>
  
  <p></p>
  
  <p>Here is the error I get : </p>
  
  <pre><code>java.lang.LinkageError: loader constraint violation: when resolving method "org.apache.jasper.runtime.InstanceManagerFactory.getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager;" the class loader (instance of org/apache/jasper/servlet/JasperLoader) of the current class, org/apache/jsp/WEB_002dINF/views/agreement2/index_jsp, and the class loader (instance of java/net/URLClassLoader) for resolved class, org/apache/jasper/runtime/InstanceManagerFactory, have different Class objects for the type .getInstanceManager(Ljavax/servlet/ServletConfig;)Lorg/apache/tomcat/InstanceManager; used in the signature
  </code></pre>
  
  <p>I think it has a relation with el or jsp-api version, I try to add manually in the pom.xml but got same error or sometimes 'noClassDefFoundError on my compiled jsp'</p>
  
  <p>Does someone see what's going wrong?</p>