difference in declaring your string array

Question

Whats the difference between this :

String [] columns = new String []{KEY_ROWID, KEY_TITLE, KEY_DESC, KEY_TIME};

And This :

String [] columns={KEY_ROWID, KEY_TITLE, KEY_DESC, KEY_TIME};

Answer 1

None.

The latter version is a handy shortcut syntax that will only work in declaration statements, but the result is exactly the same.

Answer 2

They produce the same instantiation (only usable in declarations) of the string array, no difference at all in the result obtained. However, I mostly choose the first one (just a personal preference).

EDIT: Sorry, I was typing while the 1st answer appeared.

Answer 3

The first line uses an array creation expression that contains an array initializer, and the second line contains just the array initializer. Here, they perform the same exact function -- create and initialize an array. But only one is only valid when declaring the array.

The array initializer is defined in the JLS, Section 10.6 :

An array initializer may be specified in a declaration (§8.3, §9.3, §14.4), or as part of an array creation expression (§15.10)

 ArrayInitializer: { VariableInitializersopt ,opt } VariableInitializers: VariableInitializer VariableInitializers , VariableInitializer 

and Section 15.10 defines the array creation expression to require new SomeType[] :

An array creation expression is used to create new arrays (§10).

 ArrayCreationExpression: new PrimitiveType DimExprs Dimsopt new ClassOrInterfaceType DimExprs Dimsopt new PrimitiveType Dims ArrayInitializer new ClassOrInterfaceType Dims ArrayInitializer DimExprs: DimExpr DimExprs DimExpr DimExpr: [ Expression ] Dims: [ ] Dims [ ] 

So, you can omit the new SomeType[] part if it's part of the declaration of the array variable, but you must include it elsewhere, such as an assignment expression.