What is the order of execution of non-static blocks with respect to a constructor in Java?

Whenever an object is created, a non-static block will be executed before the execution of the constructor.

Non-Static Blocks

• The Non-static blocks are class level blocks which do not have any prototype.
• The need for a non-static block is to execute any logic whenever an object is created irrespective of the constructor.
• The Non-static blocks are automatically called by the JVM for every object creation in the java stack area.
• We can create any number of Non-static blocks in Java.
• The order of execution of non-static blocks is an order as they are defined.

Example

Live Demo

public class NonStaticBlockTest {
   {
      System.out.println("First Non-Static Block"); // first non-static block
   }
   {
      System.out.println("Second Non-Static Block"); // second non-static block
   }
   {
      System.out.println("Third Non-Static Block"); // third non-static block
   }
   NonStaticBlockTest() {
      System.out.println("Execution of a Constructor"); // Constructor
   }
   public static void main(String args[]) {
      NonStaticBlockTest nsbt1 = new NonStaticBlockTest();
      NonStaticBlockTest nsbt2 = new NonStaticBlockTest();
   }
}

Output

First Non-Static Block
Second Non-Static Block
Third Non-Static Block
Execution of a Constructor
First Non-Static Block
Second Non-Static Block
Third Non-Static Block
Execution of a Constructor