Saturday, May 7, 2011

chapter 9

When an object reference is passed to a method, the method may change the values in the object.
==true

You cannot use the fully-qualifed name of an enum constant for this.
==a case expression***

Look at the following declaration.

enum Tree { OAK, MAPLE, PINE }

What is the ordinal value of the MAPLE enum constant?
==1

If the this variable is used as a constructor call,
=A compiler error will result, if it is not the first statement of the constructor

A class's static methods do not operate on the fields that belong to any instance of the class.
==true

If you have defined a class SavingsAccount with a public static method getNumberOfAccounts(), and created a SavingsAccount object referenced by the variable account20, which of the following will call the getNumberOfAccounts()method?
==SavingsAccount.getNumberOfAccounts();


The JVM periodically performs this process to remove unreferenced objects from memory.
==garbage collection

If the following is from the method section of a UML diagram, which of the following statements is true?

+ equals(object2:Stock) : boolean
==This is a public method that accepts a FeetInches object as its argument and returns a boolean value

You may use this to compare two enum data values.
==The equals and compareTo methods that automatically come with the enum data type


Look at the following declaration.

enum Tree { OAK, MAPLE, PINE }

What is the fully-qualified name of the PINE enum constant?
==Tree.PINE

If the this variable is used as a constructor call,
==A compiler error will result if it is not the first statement of the constructor

To copy an object to another object of the same class
==Write a copy method that will make a field by field copy of the two objects

Enumerated types have this method, which returns the position of an enum constant in the declaration list.
==ordinal

If you have defined a class named SavingsAccountwith a public static data member namednumberOfAccounts, and created a SavingsAccountobject referenced by the variable account20, which of the following will assign numberOfAccounts tonumAccounts?
==numAccounts = SavingsAccount.numberOfAccounts;

When a method's return type is a class, what is actually returned to the calling program?
==A reference to an object of that class

The only limitation that static methods have is
==They cannot refer to non-static members of the class

When the this variable is used to call a constructor,
==. It must be the first statement in the constructor making the call


You can declare an enumerated data type inside of a method.
==false

The term for the relationship created by object aggregation is
==Has a


If you write a toString method to display the contents of an object, object1, for a class, Class1, then the following two statements are equivalent:

System.out.println(object1);
System.out.println(object1.toString());
~~true


You cannot use the fully-qualifed name of an enum constant for this
~~a case expression

To compare two objects
~~Write an equals method that will make a field by field comparison of the two object

What will be returned from a method, if the following is the method header:

public Rectangle getRectangle()
~~The address of an object in the class Rectangl


An instance of a class does not have to exist in order for values to be stored in a class's static fields
~~~true

If you write a toString method for a class, Java will automatically call the method any time you concatenate an object of the class with a string.
~~true

Which of the following is not true about static methods?
~~They are called from an instance of the class.

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