We added support for TLS 1.2 in JDK 7 (July 2011) although it was not the default. JDK 8 (March 2014) will use TLS 1.2 as the default.
OpenSSL added support for TLS 1.2 in version 1.0.1 (March 2012). Most Linux distributions and scripting languages use OpenSSL.
Microsoft supported TLS 1.2 in Windows 7. Internet Explorer and .NET follow accordingly. TLS 1.2 was first enabled by default in Internet Explorer 11 (October 2013).
Firefox turned TLS 1.2 on by default in version 27 (February 2014).
Chrome supported TLS 1.2 in version 29 (August 2013).