考证书will he but not necessary

As a JAVA developer with years of experience, you are great! People know you are smart.
Besides Java, I am sure you knew other programming language too.
I wish Oracle will continue support JAVA, in that case, there is nothing for you to worry about (in a short time).
In the meantime, you can easily transfer to a developer do other kind of coding like C++, PHP, or C# on .net.

Thanks!