How to implement single sign-on for two PHP applications and one Java application

How can I implement single-point logon between two PHP applications and one Java application? I would like to ask two PHP applications and one Java application. the databases of each application are isolated from each other, but they are in the same domain: app1.domain.com, app2.domain.com, and app3.domain. comPHP: how does one implement single sign-on for two PHP applications and one Java application?
I would like to ask two PHP applications and one Java application. the databases of each application are isolated from each other, but they are in the same domain:
For example, app1.domain.com, app2.domain.com, and app3.domain.com
PHP is developed based on Apahce + PHP 5.2, and Java applications are developed based on GlassFish 3.1.2.

Is there any way to achieve single-point logon?

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Java
Cookie myCookie = new Cookie ......
MyCookie. setDomain (".domain.com ");
......


Php

Setcookie ("key", $ value, $ time, "/", ".domain.com ");





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Passing the login information through js does not matter whether it is in the same domain
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Create a public identity authentication system.
When a user logs on to an application system, a unique token is sent to the user. when the user accesses other applications, the token is used. the identity authentication system determines that the user has logged on.
For specific implementation, refer to the SSO systems of many companies.

For web applications, the simplest method is cookie.