Getting compiler error while using array constants in the constructor
public class Sonnet29 implements Poem {
private String[] poem;
public Sonnet29() {
poem = { "foo", "bar" , "baz"};
}
@Override
public void recite() {
//...
}
}
Line poem = { "foo", "bar" , "baz"};
is giving compilation error.
Any specific reason why this is not allowed? How do I initialize a String array with array constants?
EDIT: Thank you folks for your answers. Now I'm clear what is allowed and what is NOT. But can I ask you why this is NOT allowed?
String[] pets;
pets = {"cat", "dog"};
After go开发者_C百科ogling a bit, I found this link, where in, it is told that coding like this leaves the compiler in ambiguity - whether the pets should be array of Strings or array of Objects. However from the declaration, it can very well figure out that it is a String array, right???
This will do what you're looking for:
public Sonnet29() {
poem = new String[] { "foo", "bar", "baz" };
}
Initialization lists are only allowed when creating a new instance of the array.
From the Java language specification:
An array initializer may be specified in a declaration, or as part of an array creation expression (§15.10), creating an array and providing some initial values
In short, this is legal code:
private int[] values1 = new int[]{1,2,3,4};
private int[] values2 = {1,2,3,4}; // short form is allowed only (!) here
private String[][] map1 = new String[][]{{"1","one"},{"2","two"}};
private String[][] map2 = {{"1","one"},{"2","two"}}; // short form
List<String> list = Arrays.asList(new String[]{"cat","dog","mouse"});
and this is illegal:
private int[] values = new int[4];
values = {1,2,3,4}; // not an array initializer -> compile error
List<String> list = Arrays.asList({"cat","dog","mouse"}); // 'short' form not allowed
{"cat", "dog"}
Is not an array, it is an array initializer.
new String[]{"cat", "dog"}
This can be seen as an array 'constructor' with two arguments. The short form is just there to reduce RSI.
They could have given real meaning to {"cat", "dog"}, so you could say things like
{"cat", "dog"}.length
But why should they make the compiler even harder to write, without adding anything useful? (ZoogieZork answer can be used easily)
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