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Arrays question

 
Greenhorn
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Hi!



i cannot understand how they have put Arrays.toString() like that, without first creating an Arrays object. Are java.util' classes are always used that way? Please explain.

Thanks a lot.
 
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Kasun Liyanage wrote:

i cannot understand how they have put Arrays.toString() like that, without first creating an Arrays object. Are java.util' classes are always used that way? Please explain.



Here is the Java doc for Arrays.toString(Object[]) method:


public static String toString(Object[] a)

Returns a string representation of the contents of the specified array. If the array contains other arrays as elements, they are converted to strings by the Object.toString() method inherited from Object, which describes their identities rather than their contents.

The value returned by this method is equal to the value that would be returned by Arrays.asList(a).toString(), unless a is null, in which case "null" is returned.

Parameters:
a - the array whose string representation to return
Returns:
a string representation of a

 
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I think you would have to see what String.split() method accomplishes and this would clear your doubt to some extent.
 
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You cannot create an object of the Arrays class.
 
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Kasun Liyanage wrote:i cannot understand how they have put Arrays.toString() like that, without first creating an Arrays object. Are java.util' classes are always used that way? Please explain.



To address this specifically, the Arrays.toString() method is a static method, so it gets called without an instance. See the java.util.Arrays javadoc and Tutorial for more.
 
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yeah, it is kind of like the Math class. you don't instantiate it you just call its static methods. and yes there are several utilities classes that follow this pattern, they are a convenience.
 
Kasun Liyanage
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Thanks a lot guys. Gonna checkout more about classes with static methods. Appreciate it.

-Kasun
 
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