SSL handshake exception in NetBeans 12.6 IDE for plugin upgrade, Can't install nb-javac plugin

Question

I freshly installed NetBeans IDE 12.6 with JDK 11.0 . On first startup it prompts for nb-javac plugin to be installed, which is fine. But when I try to install Netbeans can't connect to plugin portals configured. Proxy settings are fine and connection test under proxy settings is successful. Under IDE log $HOME/.netbeans/12.6/var/log/messages.log it shows a SSL handshake exception with message that remote peer terminated connection.

Answer 1

After some digging I found that adding a JVM options to use TLSv1.2 resolves this problem. Edit Netbeans configuration file $NETBEANS_DIR/netbeans/etc/netbeans.conf to add JVM option. Add -J-Dhttps.protocols=TLSv1.2 at the end for netbeans_default_options param, as below

netbeans_default_options=" <Already present options> -J-Dhttps.protocols=TLSv1.2"

Save the file and restart IDE. Try to install plugin again, and it works !!!