Why are booleans not considered an object?
Simply put, primitive types like boolean, int, float, and double are not objects because they are not a subclass of Object. Additionally, they do not have methods. Here are two good answers for this question:
https://www.baeldung.com/java-primitives-vs-objects
(Links to an external site.)https://www.quora.com/What-is-the-difference-between-an-integer-and-int-in-Java
When are primitive booleans best used?
Booleans are most often used within if statements and while loops. Booleans are used whenever a truth value should be stored to be later referenced. For instance, if a truth value would otherwise be computed multiple times, it might be easier and more efficient to store the truth value in a boolean variable.
https://www.dotnetperls.com/boolean-java
How can boolean values be combined?
Since a boolean is just a truth value, the combination of boolean variables and operations are treated as a combination of truth values.
Simple combinations can be seen here:
https://www.dotnetperls.com/boolean-java
While more complex truth value operations can be seen here:
https://rosettacode.org/wiki/Truth_table