Why does opening a java nio selector result in a socket level connection being created on a dynamic

[Sudarshan Sreenivasan]

I am trying to understand how the Java NIO library works ...

I have written some code which just opens multiple selectors

public static void main(String[] args) throws IOException, InterruptedException {

    Selector incomingMessageSelector = Selector.open();
    Selector incomingMessageSelector1 = Selector.open();
    Selector incomingMessageSelector2 = Selector.open();               
    Thread.sleep(900000L);
}

Each time when i open a selector i can see connections being created at the socket level, so for example in this case 3 connections get created.

In the below image i have highligted those 3 connections being made to dynamic ports ...

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