Java: When is a static initialization block useful?

Question

What\'s the difference between initialization within a static block:

public class staticTest {

    sta         


        

Answer 1

The static code block enables to initialize the fields with more than instuction, initialize fields in a different order of the declarations and also could be used for conditional intialization.

More specifically,

static final String ab = a+b;
static final String a = "Hello,";
static final String b = ", world";

will not work because a and b are declared after ab.

However I could use a static init. block to overcome this.

static final String ab;
static final String a;
static final String b;

static {
  b = ", world";
  a = "Hello";
  ab = a + b;
}

static final String ab;
static final String a;
static final String b;

static {
  b = (...) ? ", world" : ", universe";
  a = "Hello";
  ab = a + b;
}