I was updating a legacy code base in Java and I found a line like this:
Object arg[] = { new Integer(20), new Integer(22) };
That line catched my attention because I am used to this kind of code:
Object[] arg = { new Integer(20), new Integer(22) };
The content of the array isn't important here. I'm curious about the brackets next to the variable name versus the brackets next to the class name. I tried in Eclipse (with Java 5) and both lines are valid for the compiler.
Is there any difference between those declarations?
Both are legal and both work. But placing [] before the array's name is recommended.
From Javadocs:
You can also place the square brackets after the array's name:
float anArrayOfFloats[]; // this form is discouraged
However, convention discourages this form; the brackets identify the array type and should appear with the type designation.
No, they both work. But watch out:
float anArrayOfFloats[], aSecondVariable;
will declare one array of floats and one float, while:
float[] anArrayOfFloats, aSecondVariable;
will declare two arrays of floats.
There is no difference. Both are legal.
You can read in Java Language Specification http://java.sun.com/docs/books/jls/second_edition/html/arrays.doc.html
The [] may appear as part of the type
at the beginning of the declaration,
or as part of the declarator for a
particular variable, or both, as in
this example:
byte[] rowvector, colvector, matrix[];
Another good reason to write Integer[] ints instead of Integer ints[] is because of inheritance relations: Integer[] is subtype of Number[] is subtype of Object[].
In other words, you can put Integers in an Object array, so you can think of the [] as part of the object's type definition -- which is why it makes sense to have it close to the type instead of the object name.
