Boolean

[krussi rong]

Hi,
here is the question:
Given these code snippets,
1. Boolean b1=new Boolean(true);
2. Boolean b2=new Boolean(true);
which expressions are legal JAVA expressions that
return true? Select all valid answers.
a. b1==b2
b. b1.equals(b2)
c. b1 & b2
d. b1 || b2
why just b is correct? not C or d?
thanks
Krussi

[Francisco A Guimaraes]

c causes a compile error because b1 and b2 are not numeric values

d causes a compile error because b1 is Boolean, the wrapper class, and not boolean, the primitive type.

Hope your doubt is cleared,
Francisco
[ May 28, 2002: Message edited by: Francisco A Guimaraes ]

[Jessica Sant]

because you're talking about the WRAPPER class Boolean, not the PRIMITIVE class boolean.
Therefore you need to compare them like objects --> with the .equals(Object) method "Returns true if and only if the argument is not null and is a Boolean object that represents the same boolean value as this object."
the equality operator and comparitive operators ==, & and || require the two values to be of the primitive type boolean. If you wanted to do those comparisons with the Wrapper class Boolean you'd need to adjust them to this:
b1.booleanValue() == b2.booleanValue();
b1.booleanValue() & b2.booleanValue();
b1.booleanValue() || b2.booleanValue();

[bob towers]

I presume you mean:
b1.booleanValue() && b2.booleanValue();
regs
bob

[Gautam Sewani]

It can be b1.booleanValue() & b2.booleanValue() as well

[krussi rong]

thanks very much!
Krussi