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Static Blocks in Java - GeeksforGeeks

Static Blocks in Java

Last Updated : 27 Jul, 2025

Whenever we use a static keyword and associate it to a block, then that block is referred to as a static block. Java supports static block (also called static clause) that can be used for static initialization of a class. This code inside the static block is executed only once: the first time the class is loaded into memory. 

Calling of static block in Java?

In order to call any static block, there is no specified way, as a static block executes automatically when the class is loaded in memory.

Illustration:

Java
class GFG {

        // Constructor of this class
        GFG() {}
        
        // Method of this class
        public static void print() { }
        
        static{}

        public static void main(String[] args) {

                // Calling of method inside main()
                GFG geeks = new GFG();

                // Calling of constructor inside main()
                new GFG();

                // Calling of static block
                // Nothing to do here as it is called
                // automatically as class is loaded in memory

        }
}

Note: From the above illustration, we can perceive that static blocks are automatically called as soon as the class is loaded in memory, and there is nothing to do as we have to in case of calling methods and constructors inside main(). 

Can we print something on the console without creating a main() method?

It is a very important question from the interview's perceptive point. The answer is yes we can print if we are using JDK version 1.6 or previous and if after that  it will throw an. Error. 

Example 1-A:  Running on JDK version 1.6 of the Previous

Java
class GFG {
  
    // Static block
    static
    {
        // Print statement
        System.out.print(
            "Static block can be printed without main method");
    }
}

Output:

Static block can be printed without the main method

Example 1-B: Running on JDK version 1.6 and later

Java
class GFG {
  
    // Static block
    static
    {
        // Print statement
        System.out.print(
            "Static block can be printed without main method");
    }
}

Output: 

Execution of Static Block

Example 1:

Java
class Test {

    // Case 1: Static variable
    static int i;
    // Case 2: non-static variables
    int j;

    // Case 3: Static block
    static
    {
        i = 10;
        System.out.println("static block called ");
    }
    // End of static block
}

// Class 2
class GFG {

    // Main driver method
    public static void main(String args[])
    {
        System.out.println(Test.i);
    }
}

Output
static block called 
10


Remember: Static blocks can also be executed before constructors.

Example 2:

Java
class Test {

    // Case 1: Static variable
    static int i;
    // Case 2: Non-static variable
    int j;

    // Case 3: Static blocks
    static
    {
        i = 10;
        System.out.println("static block called ");
    }

    // Constructor calling
    Test() { System.out.println("Constructor called"); }
}

class GFG {

    // Main driver method
    public static void main(String args[])
    {

        // Although we have two objects, static block is executed only once.
        Test t1 = new Test();
        Test t2 = new Test();
    }
}

Output
static block called 
Constructor called
Constructor called

A class can have any number of static initialization blocks, and they can appear anywhere in the class body. The runtime system guarantees that static initialization blocks are called in the order that they appear in the source code.

Note: We use an Initializer Block in Java if we want to execute a fragment of code for every object, which is seen widely in enterprising industries in development. 



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