title: Eclipse: Could not instrument class exception after upgrading to Spring Boot 2.0.1
body: <p>After upgrading a Vaadin Spring Boot project from 1.5.9 to 2.0.1, I am getting multiple <code>Could not instrument class...</code> exceptions when starting the application in Eclipse with <code>spring-boot:run</code>. Executing the application from the command line with spring-boot:run does not display the exceptions.</p>
  
  <p>Without success I've already tried to clean the project in Eclipse, update the maven projects and to delete the .m2 folder. </p>
  
  <p>The application itself seems to run without obvious problems, both if started from the command line or from Eclipse.</p>
  
  <p>One of the exceptions displayed if I start Spring Boot from Eclipse:</p>
  
  <pre><code>[INFO] --- spring-boot-maven-plugin:2.0.1.RELEASE:run (default-cli) @ project ---
  Could not instrument class org/hibernate/validator/internal/engine/valueextraction/ObservableValueValueExtractor: java.lang.RuntimeException
  at com.ifedorenko.org.objectweb.asm.ClassVisitor.visitTypeAnnotation(Unknown Source)
  at com.ifedorenko.org.objectweb.asm.ClassReader.accept(Unknown Source)
  at com.ifedorenko.org.objectweb.asm.ClassReader.accept(Unknown Source)
  at com.ifedorenko.m2e.sourcelookup.javaagent.ClassfileTransformer.transform(ClassfileTransformer.java:27)
  at com.ifedorenko.m2e.sourcelookup.javaagent.Premain$1.transform(Premain.java:55)
  at sun.instrument.TransformerManager.transform(TransformerManager.java:188)
  at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)
  at java.lang.ClassLoader.defineClass1(Native Method)
  at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
  at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
  at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
  at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
  at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
  at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
  at java.security.AccessController.doPrivileged(Native Method)
  at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
  at org.hibernate.validator.internal.engine.valueextraction.ValueExtractorManager.&lt;clinit&gt;(ValueExtractorManager.java:43)
  at org.hibernate.validator.internal.engine.ValidatorFactoryImpl.&lt;init&gt;(ValidatorFactoryImpl.java:140)
  at org.hibernate.validator.HibernateValidator.buildValidatorFactory(HibernateValidator.java:38)
  at org.hibernate.validator.internal.engine.ConfigurationImpl.buildValidatorFactory(ConfigurationImpl.java:364)
  at org.springframework.boot.autoconfigure.BackgroundPreinitializer$ValidationInitializer.run(BackgroundPreinitializer.java:142)
  at org.springframework.boot.autoconfigure.BackgroundPreinitializer$1.runSafely(BackgroundPreinitializer.java:92)
  at org.springframework.boot.autoconfigure.BackgroundPreinitializer$1.run(BackgroundPreinitializer.java:82)
  at java.lang.Thread.run(Thread.java:745)
  </code></pre>
  
  <p>My setup:</p>
  
  <ul>
  <li>Java 8 JDK 171</li>
  <li>Eclipse Oxygen.3a</li>
  <li>Spring Boot 2.0.1</li>
  <li>Maven 3.3.9</li>
  </ul>
  
  <p>Any idea how I can get rid of or what causes the exceptions?</p>