What does Static {} mean in the Java Syntax?

Question

I came across this Java code:

static {     String aux = "value";     try {         // some code here     } catch (Exception e) { }     String UUID_prefix = aux + ":"; } 

I am new to Java, please explain what is happening here.

Answer 1

This is a static initialization block. Think of it like a static version of the constructor. Constructors are run when the class is instantiated; static initialization blocks get run when the class gets loaded.

You can use them for something like this (obviously fabricated code):

private static int myInt;  static {     MyResource myResource = new MyResource();     myInt = myResource.getIntegerValue();     myResource.close(); } 

See the "Static Initialization Blocks" section of Oracle's tutorial on initializing fields.

Answer 2

This is the block of code that will get invoked when your class is loaded by classloader