code: public Context getContext() {
          if (context == null) {
              try {
                  context = new InitialContext(createProperties());
              } catch (NamingException e) {
                  throw new IllegalStateException("Unable to create context", e);
              }
          }
          return context;
      }
docs: Gets the initial JNDI context, if not set uses the jndi settings and `initialContextFactory` to create
  a JNDI initial context.
  
  @return JNDI initial context.
  @see JmsServiceBuilder#context
  @see JmsServiceBuilder#initialContextFactory
  @see JmsServiceBuilder#jndiSettings