how to initialize a static array of objects in java

Question

Basically I want to create a data structure of values already known at compile time. In C I'd do it like this:

struct linetype { int id; char *descr; };

static struct linetype mylist[] = {
    { 1, "first" },
    { 2, "second" }
};

The only soultion I have found in Java involves creating the array at runtime:

public class Outer {

    public class LineType {
        int id;
        String descr;

        private LineType( int a, String b) {
          this.id = a;
          this.descr = b;
        }
    }

    LineType[] myList = { 
        new LineType( 1, "first" ),
        new LineType( 2, "second" ),
    };

This appears cumbersome and ineffective (when the structures get long and complex). Is there another way?

(NB: please disregard any syntax errors as this is only sample code created for this question. Also, I am aware a String is somethign else than a character pointer pointing into the data segment. However, the argument works with primitive data types as well).

Answer 1

You have to make LineType a static class:

public class Outer {

    public static class LineType {
        int id;
        String descr;

        private LineType( int a, String b) {
          this.id = a;
          this.descr = b;
        }
    }

    static LineType[] myList = { 
        new LineType( 1, "first" ),
        new LineType( 2, "second" ),
    };
}

Answer 2

In Java, you can't create arrays at compile time (arrays are special type of objects). Either class load time using static blocks (or) runtime (as instance variable) you can create arrays.

Example static block:

class TestClass
{
     static {
     arr[0] = "Hi";     
     arr[1] = "Hello";     
     arr[2] = "How are you?"; 
    }
....
}