spring security

• login-page – the custom login page
• default-target-url – the landing page after a successful login
• authentication-failure-url – the landing page after an unsuccessful login
• https://spring.io/guides/gs/securing-web/ how-to-disable-spring-security-for-particular-url
• for checked attribute it should be written like checked="checked"
• single sign on
• Single sign-on (SSO) is a property of access control of multiple related, yet independent, software systems. With this property, a user logs in with a single ID and password to gain access to a connected system or systems without using different usernames or passwords, or in some configurations seamlessly sign on at each system. This is typically accomplished using the Lightweight Directory Access Protocol (LDAP) and stored LDAP databases on (directory) servers.^[1] A simple version of single sign-on can be achieved over IP networks using cookies but only if the sites share a common DNS parent domain.^[2]
  For clarity, it is best to refer to systems requiring authentication for each application but using the same credentials from a directory server as Directory Server Authentication and systems where a single authentication provides access to multiple applications by passing the authentication token seamlessly to configured applications as Single Sign-On.
  Conversely, single sign-off is the property whereby a single action of signing out terminates access to multiple software systems.
  
  google is an example of sso. by logging to gmail we can use blogger, youtube etc
  and once we logout of any of the services then we can no longer use any of the connected services. 
• what-is-and-how-does-single-sign-on-work/ 
•  httpsecurity-websecurity-and-authenticationmanagerbuilder
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