java.lang.LinkageError: loader constraint violation:previously initiated loading for a different type with name "javax/mail/Session"

As suggested in comments, add your dependency to javamail as provided dependency:

<dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.5.1</version>
        <scope>provided</scope>
</dependency>

This will skip adding duplicate jars which would then be loaded by different classloaders.

If not somehow forced to use old version of javamail you should update to latest which is currently

<dependency>
        <groupId>com.sun.mail</groupId>
        <artifactId>javax.mail</artifactId>
        <version>1.5.5</version>
        <scope>provided</scope>
</dependency>