POJI in Java

POJI is an abbreviation for Plain Old Java Interface, which corresponds to Java standard interfaces, meaning these interfaces are provided in the context of services in JEE. For example, OSGi services are provided through POJI in JEE

In other words, we can say that POJI is a common interface with no special that cannot be inherited from any technology API-specific interface or framework interface.

Example

interface myCustomInterface {
　　　public void myMethod();
}
interface mySecondCustomInterface extends myCustomInterface {
　　　public void mySecondMethod();
}

These interfaces are both called POJI because they do not inherit any technology-specific interfaces.

Example

interface GFG1　extends java.rmi.Remote {
　　　public void myMethod();
}
interface GFG2　extends java.beans.AppletInitializer {
　　　public void mySecondMethod();
}

These interfaces will not be called POJI because they inherit interfaces specific to technology.