A class will have the following contents. When class is initialized, they are in order

• Static properties: properties defined at the beginning of static
• Static method block: method block circled by static {}
• Static method: static decorated method (only effective when called)
• Common attribute: attribute without static definition
• Common method block: method block circled by {}
• Normal method: normal method (only effective when called)
• Constructor: method with the same class name

1. general category

public class LifeCycle {
    // Static attribute
    private static String staticField = getStaticField();
    // Static method block
    static {
        System.out.println(staticField);
        System.out.println("Static method block");
    }
    // Static method
    public static String getStaticField() {
        System.out.println("Static method");
        return "Static attribute";
    }
    // General attribute
    private String field = getField();
    // Common method block
    {
        System.out.println(field);
        System.out.println("Common method block");
    }
    // Common method
    public static String getField() {
        System.out.println("Common method");
        return "General attribute";
    }
    // Construction method
    public LifeCycle() {
        System.out.println("Construction method");
    }

    // Main function
    public static void main(String[] argc) {
        new LifeCycle();
    }
}

The initialization sequence is as follows

• Static attribute
• Static method block
• General attribute
• Common method block
• Construction method

2. inheritance

public class LifeCycleFather {
    // Static attribute
    private static String staticField = getStaticField();
    // Static method block
    static {
        System.out.println(staticField);
        System.out.println("Parent static method block");
    }
    // Static method
    public static String getStaticField() {
        System.out.println("Parent static method");
        return "Parent static properties";
    }
    // General attribute
    private String field = getField();
    // Common method block
    {
        System.out.println(field);
        System.out.println("Parent common method block");
    }
    // Common method
    public static String getField() {
        System.out.println("Parent common method");
        return "Parent common property";
    }
    // Construction method
    public LifeCycleFather() {
        System.out.println("Construction method of parent class");
    }
}

public class LifeCycle extends LifeCycleFather{
    // Static attribute
    private static String staticField = getStaticField();
    // Static method block
    static {
        System.out.println(staticField);
        System.out.println("Static method block");
    }
    // Static method
    public static String getStaticField() {
        System.out.println("Static method");
        return "Static attribute";
    }
    // General attribute
    private String field = getField();
    // Common method block
    {
        System.out.println(field);
        System.out.println("Common method block");
    }
    // Common method
    public static String getField() {
        System.out.println("Common method");
        return "General attribute";
    }
    // Construction method
    public LifeCycle() {
        System.out.println("Construction method");
    }

    // Main function
    public static void main(String[] argc) {
        new LifeCycle();
    }
}

Initialization order

• Parent static properties
• Parent static code block
• Subclass static properties
• Subclass static code block
• Parent common property
• Parent normal code block
• Construction method of parent class
• Subclass common properties
• Subclass common code block
• Subclass construction method