When you try to send mail from code and you find the error "The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.5.1 Authentication Required", than the error might occur due to following cases.
case 1: when the password is wrong case 2: when you try to login from some App case 3: when you try to login from the domain other than your time zone/domain/computer (This is the case in most of scenarios when sending mail from code)
There is a solution for each Solution for case 1: Enter the correct password.
solution 1 for case 3: (This might be helpful) you need to review the activity. but reviewing the activity will not be helpful due to latest security standards the link will not be useful. So try the below case.
solution 2 for case 3: If you have hosted your code somewhere on production server and if you have access to the production server, than take remote desktop connection to the production server and try to login once from the browser of the production server. This will add excpetioon for login to google and you will be allowed to login from code.
But what if you don't have access to the production server. try the solution
solution 3 for case 3: You have to enable login from other timezone / IP for your google account.
to do this follow the link https://g.co/allowaccess and allow access by clicking the continue button.
And that's it. Here you go. Now you will be able to login from any of the computer and by any means of app to your google account.
1: Open file /etc/apache2/sites-enabled/000-default.conf
2: Change content
3: Restart apache2
<VirtualHost *:80> # The ServerName directive sets the request scheme, hostname and port that # the server uses to identify itself. This is used when creating # redirection URLs. In the context of virtual hosts, the ServerName # specifies what hostname must appear in the request's Host: header to # match this virtual host. For the default virtual host (this file) this # value is not decisive as it is used as a last resort host regardless. # However, you must set it for any further virtual host explicitly. #ServerName www.example.com
ServerAdmin webmaster@localhost ProxyRequests Off
Allow from all
ProxyPass / http://localhost:8080/ DocumentRoot /var/www/html
# Available loglevels: trace8, ..., trace1, debug, info, notice, warn, # error, crit, alert, emerg. # It is also possible to configure the loglevel for particular # modules, e.g. #LogLevel info ssl:warn
# For most configuration files from conf-available/, which are # enabled or disabled at a global level, it is possible to # include a line for only one particular virtual host. For example the # following line enables the CGI configuration for this host only # after it has been globally disabled with "a2disconf". #Include conf-available/serve-cgi-bin.conf
First, let's have a clear idea of the following terms
Javac is Java Compiler -- Compiles your Java code into Bytecode
JVM is Java Virtual Machine -- Runs/ Interprets/ translates Bytecode into Native Machine Code
JIT is Just In Time Compiler -- Compiles the given bytecode instruction sequence to machine code at run-time before executing it natively. It's main purpose is to do heavy optimizations in performance.
So now, Let's find answers to your questions..
1)JVM: is it a compiler or an interpreter? -- Ans: Interpreter
2)what about JIT compiler that exist inside the JVM? -- Ans: If you read this reply completely, you probably know it now
3)what exactly is the JVM? -- Ans:
JVM is a virtual platform that resides on your RAM
Its component, Class loader loads the .class file into the RAM
The Byte code Verifier component in JVM checks if there are any access restriction violations in your code. (This is one of the principle reasons why java is secure)
Next, the Execution Engine component converts the Bytecode into executable machine code