Are we instantiating interface in Strategy Pattern? [duplicate]

https://www.javatpoint.com/strategy-pattern

I have heard that we can't initiate (make objects) of interfaces, but in Strategy Pattern, we are creating an object of Strategy interface.

Code

public interface Strategy {  
      public float calculation(float a, float b);  
}

public class Context {  
  
       **private Strategy strategy;**  
       
       public Context(Strategy strategy){  
          this.strategy = strategy;  
       }  
  
       public float executeStrategy(float num1, float num2){  
          return strategy.calculation(num1, num2);  
       }  
}

In context class, we have created an object of Strategy interface. How is this possible as interfaces can't be instantiated.