What is the use of static block and constructor in java.

Question

static block is used to execute a code(logic which u want to execute first with out using object) as soon as class is loaded.
constructor is used to execute logic when object is created for that class.

Answer 1

static block is similar for classes as constructors for objects. In a constructor you can initialize object properties, in a static block you can initialize class properties.

Answer 2

Static block executed once while class-loading or initialize by JVM.
constructor executed every time while creating instance of that class.

Here is the example.

public class program
{
static{
System.out.println("Static block");
}
program(){
System.out.println("Constructor");
}
public static void main(String[] args) {
program p1 = new program();
program p2 = new program();
}
}

Output:
Static block
Constructor
Constructor