double object's method comparison

[vb_student]

Hello

can you guys tell me if there is a difference between these two sections of code

x = Double.parseDouble( xChars );

x   = ( Double.valueOf( xChars ) ).doubleValue();

[ComputerJy]

About "Double.valueOf":

Returns a Double object holding the double value represented by the argument string s.

If s is null, then a NullPointerException is thrown.

Leading and trailing whitespace characters in s are ignored. The rest of s should constitute a FloatValue as described by the lexical rule:

FloatValue:
Signopt NaN
Signopt Infinity
Signopt FloatingPointLiteral

where Sign and FloatingPointLiteral are as defined in §3.10.2 of the Java Language Specification. If s does not have the form of a FloatValue, then a NumberFormatException is thrown. Otherwise, s is regarded as representing an exact decimal value in the usual "computerized scientific notation"; this exact decimal value is then conceptually converted to an "infinitely precise" binary value that is then rounded to type double by the usual round-to-nearest rule of IEEE 754 floating-point arithmetic, which includes preserving the sign of a zero value. Finally, a Double object representing this double value is returned.

To interpret localized string representations of a floating-point value, use subclasses of NumberFormat.



While "Double.parseDouble":

Returns a new double initialized to the value represented by the specified String, as performed by the valueOf method of class Double

[vb_student]

thanks for the reply

i geuss the two sections of code are equivalent?
i guess this is not possible

double xChars
xChars.doubleValue()

i guess xChars is not an object, but a value in this code?

[ComputerJy]

Correct, in java there is a difference between primitive data types (int, char, boolean, short...) and class objects (Integer, Character, Boolean, Short...) Not like in Visual Languages

[vb_student]

& double is a primitie data type.

would Integer be an object holiding an integer value?

[ComputerJy]

Yes, exactly, it holds int value with some methods to use

[vb_student]

thanks