Difference between the static initializer block and regular static initialization

Question

As the title says, what exactly is the difference between

public static String myString = "Hello World!";

and

public static String myString;

static {
    myString = "Hello World";
}

is there any important difference other than the structure ?

Answer 1

For your example, there is no difference. But as you can see,

public static String myString = "Hello World!";

can only accept an expression to initialize the variable. However, in a static initializer (JLS 8.7), any number of statements may be executed. E.g. it's possible to do this:

static
{
    myString = "Hello";
    myString += " ";
    myString += "World";
}

For your example, there's obviously no need to do that, but it's possible for the initialization of a variable to take more than an expression, perhaps many statements, so Java made static initializers.