I got this issue (using Mac OS X, Java 8 (1.8.0_131) and configuring the Java's Advances properties (Java Control Panel) to Enable TLS 1.2 everything start running OK again.
Is there anything special we need to do to enable the legacy java clients? I keep getting "Unable to connect to NetSight Server" (on Windows, I saw the note in the install log about Linux). Wireshark shows TLS 1.2 is being negotiated with the correct cert chain, but the client just immediate closes the connection. I've cleared the Java cache.