Add classes exercises

Author: noidontdig

exercises/classesobjects.md

@@ -11,7 +11,7 @@
 
 ###Exercises
 
-Complete these exercises in `ClassesAndObjects.java`. Please use the `Cat.java` class to complete these exercises.
+Complete these exercises in `ClassesAndObjects.java`. Please use the `Cat.java` and `Person.java` classes to complete these exercises.
 
 ####1. Cool cats
 
@@ -42,3 +42,26 @@ Write a method called `makeKitten` that takes 2 Cats as parameters and returns a
 ex: makeKitten(garfield, catwoman) returns a Cat named "GarfieldCatwoman" with age 0
 ```
 
+####5. Adoption
+
+Write a method called `adoption` that takes 1 Cat and 1 Person as a paramater and sets the Cat's owner to be the Person.
+
+```
+ex: Person jon = Person('Jon');
+    adoption(garfield, jon); // Jon is now Garfield's owner!
+```
+
+*Hint: this method does not return anything!*
+
+**Bonus Challenge**
+
+If the Cat's name is `Catwoman`, don't set the owner, but instead print: "Catwoman will never be anyone's pet!"
+
+####6. isFree
+
+Write a method called `isFree` that checks whether or not a Cat has an owner.
+
+```
+ex: isFree(garfield) returns false
+```
+

src/Cat.java

@@ -6,6 +6,7 @@ public class Cat {
   private String name;
   private String favoriteFood;
   private int age;
+  private Person owner;
 
   public Cat() {
   }
@@ -37,4 +38,12 @@ public String getName() {
   public void setName(String name) {
     this.name = name;
   }
+
+  public void setOwner(Person owner) {
+    this.owner = owner;
+  }
+
+  public Person getOwner() {
+    return owner;
+  }
 }