Java Questions 19 - Access Modifiers

1. What types of access modifiers can you use for local variables?
   
   Answer:
   The only access modifier you can use for local variables (variables within a method) is final .
   Once a local variable has been assigned a value, it can only be assigned another value if it is not final.

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2. What is the purpose of declaring a method as final?
   
   Answer:
   The final keyword prevents a method from being overridden in a subclass, and is often used to enforce the API functionality of a method.

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3. What is the purpose of the thread method isAlive() ?
   
   Answer:
   The Thread class has a method called isAlive() that checks whether a thread is still active.

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4. What is a final argument?
   
   Answer:
   

   public Record getRecord(int fileNumber, final int recNumber){}
   

   
   In this example, the variable recNumber is declared as final, which of course means it can not be modified within the method.
   A final argument must keep the same value that the parameter had when it was passed into the method.

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5. What is an abstract method?
   
   Answer:
   An abstract method is a method whose implementation is deferred to a subclass.

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6. What are the characteristics of an abstract method?
   
   Answer:
   An abstract method contains no functional code and has no method body.

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7. Can you have an abstract clalss with no abstract methods?
   
   Answer:
   Yes. You can have an abstract class with no abstract methods.

   public abstract class LegalClass{
     void goodMethod(){
     }
   } 
   

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8. What does an abstract mehod end with?
   
   Answer:
   An abstract method ends in a semicolon.

   abstract void draw(); 
   

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9. What is one difference between an abstract and non-abstract class?
   
   Answer:
   A non-abstract class is a class that can be instantiated. An abstract class can not be instantiated.

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10. What is the purpose of an abstract class?
    
    Answer:
    Abstract methods are meant to be overridden and must be implemented by a non-abstract subclass that extends the abstract class.