title: What does $$ and <generated> mean in Java stacktrace?
body: <p>I often get stacktraces like this one (please see the arrow for the confusing line):</p>
  <pre><code>org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [PRIMARY]; nested exception is org.hibernate.exception.ConstraintViolationException: could not execute statement
                  at org.springframework.orm.hibernate5.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:164)
                  at org.springframework.orm.hibernate5.HibernateTransactionManager.convertHibernateAccessException(HibernateTransactionManager.java:741)
                  at org.springframework.orm.hibernate5.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:589)
                  at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:761)
                  at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:730)
                  at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:485)
                  at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:291)
                  at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
                  at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
                  at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
  ---------&gt;      at com.panpwr.admin.services.detector.SimpleDetectorPersistenceService$$EnhancerBySpringCGLIB$$66303639.saveComplexRuleAndActionTemplates(&lt;generated&gt;)
                  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
                  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
                  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  ...
  ...
  ...
  </code></pre>
  <p>What does the <code>$$</code> sign mean, and what is the 'generated' in this line?
  <code>com.panpwr.admin.services.detector.SimpleDetectorPersistenceService$$EnhancerBySpringCGLIB$$66303639.saveComplexRuleAndActionTemplates(&lt;generated&gt;)</code></p>
  <p>And why does it only say the executed method but not the line number in it?</p>