Compound Boolean Expression

&& will make it so both parameters need to be met so that the code runs. || is the same thing but either can be true and the code will run.

public class Example1
{
   public static void main(String[] args)
   {
     boolean cleanedRoom = true;
     boolean didHomework = false;
     if (cleanedRoom && didHomework)
     {
         System.out.println("You can go out");
     }
     else
     {
         System.out.println("No, you can't go out");
     }
   }
   
}

A Truth Table shows all the possible results of a boolean function, whether it's true or false.

De Morgan's Law:

De Morgan's Law states that the "!" symbol will negate an And statement and an Or statement. This means that if a condition is written as a || b, !(a || b) would really be a && b. This goes for the other way around where !(a && b) is a || b. It will also cause a true statement to be false with !(true) and vice versa.

boolean child = true;
boolean hungry = false;

if (!(child && hungry)) {
    System.out.println("You have a hungry child");
}
else {
    System.out.println("Who knows what's going on?");
}

You have a hungry child

boolean fruit = true;
boolean red = true;

if (!(!(fruit) || !(red))) {
    System.out.println("It's probably a red apple");
}
else {
    System.out.println("You have an unknown food");
}

It's probably a red apple

Homework