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Boolean

 
krussi rong
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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
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  • 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
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    Android IntelliJ IDE Java
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    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
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    I presume you mean:
    b1.booleanValue() && b2.booleanValue();
    regs
    bob
     
    Gautam Sewani
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    It can be b1.booleanValue() & b2.booleanValue() as well
     
    krussi rong
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    thanks very much!
    Krussi
     
    Consider Paul's rocket mass heater.
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