Can Sun ever take away the code?

The simple answer to this is NO. Once code is released under the LGPL, it can 
never be taken away.  Once LGPL, always LGPL.  Sun has no plans to return to a 
closed development model.  Sun is subject to the same rules as the rest of the community, including giving back modifications under the LGPL (or a spacification and reference implementation under the terms of the SISSL).  Thus, Sun can never take away the code and the community's contributions to it.  This code belongs to the community as guaranteed by the LGPL and the SISSL.