Can I define multiple static blocks?

Question

Can I define multiple static blocks?

If possible, why should I define muliple static blocks?

Answer 1

yes, you can also make multiple initialisation blocks.

This allows you to place code with the thing initialised.

private static final Map<String, String> map;
static {
   // complex code to initialise map
}

private static final DbConnection conn;
static {
  // handle any exceptions and initialise conn
}

Answer 2

public class TryInitialisation {
static int[] values = new int[10];
static{
    System.out.println("running initialisation block");
    for (int i=0; i< values.length; i++)
        values[i] = (int) (100.0 * i);
}
static{
    System.out.println("running initialisation block");
    for (int i=0; i< values.length; i++)
        values[i] = (int) (200.0 * i);
}
static{
    System.out.println("running initialisation block");
    for (int i=0; i< values.length; i++)
        values[i] = (int) (300.0 * i);
}
void listValues(){
    for (int i=0; i<values.length; i++)
        System.out.println(" " + values[i]);
}
public static void main(String[] args) {

TryInitialisation example = new TryInitialisation();
example.listValues(); 
example = new TryInitialisation(); // referencing a new object of same type
example.listValues();
}

}

here is the output:

running initialisation block
running initialisation block
running initialisation block
0
300
600
900
1200
1500
1800
2100
2400
2700
0
300
600
900
1200
1500
1800
2100
2400
2700

The static blocks were executed serially in the order in which they were declared and the values assigned by the first two static blocks is replaced by the final (third static block).

Also one more thing to observe is that the static initialization block(s) ran only once i.e when the class was loaded by the JVM independent of how many objects were created.