Eclipse expressions view typenames

I'm trying to get more information about the trustmanager stored in a SSLContext instance via reflection. In order to do that, I'm using the Eclipse Oxygen.3a Expression viewer to view the fields of the SSLContext instance.

The first field I'm extracting is the contextSpi field. After that, it gets confusing. The contextSpi field is of type sun.security.ssl.SSLContextImpl$TLSContext.

Can someone explain what the $ in the type description means?

Also, when I reflect further on what presumably is the SSLContextImpl by using field.get(sslContextInstance).getClass().getSuperClass(), I'm getting a sun.security.ssl.SSLContextImpl$CustomizedTLSContext.

Now I'm even further at a loss. Is there a way to find out to what inherited / implemented class or interface a field in the expression viewer belongs? And then of course extract it?