官方給出了

 @CallerSensitive
    public static Class<?> forName(String className)
                throws ClassNotFoundException {
        Class<?> caller = Reflection.getCallerClass();
        return forName0(className, true, ClassLoader.getClassLoader(caller), caller);
    }


 @CallerSensitive
    public static Class<?> forName(String name, boolean initialize,
                                   ClassLoader loader)
        throws ClassNotFoundException


//私有方法，是個(gè)本地方法，直接調(diào)用C JNI  
 /** Called after security check for system loader access checks have been made. */
    private static native Class<?> forName0(String name, boolean initialize,
                                            ClassLoader loader,
                                            Class<?> caller)
        throws ClassNotFoundException;

//測(cè)試代碼

public class ClassTest {


    public static  void main(String args[]) throws IllegalAccessException, InstantiationException, ClassNotFoundException, NoSuchMethodException, InvocationTargetException {
//        Class clazz1 = A.class;
//
//        System.out.println(clazz1.newInstance().getClass().getSimpleName());
//
//
//        Class clazA = Class.forName("com.wd.bigdata.javaexample.proxy.Class.A");
//                .getConstructor(String.class,int.class,float.class)

        System.out.println("================");

        Class<?> claz = Class.forName("com.wd.bigdata.javaexample.proxy.Class.A",
                false,
                A.class.getClassLoader());

//        Object o = con.newInstance("yang",29,0.2f);
//
//        System.out.println(o.getClass().getName());
//        System.out.println(o.toString());
    }


public class A {

    private String field1;
    private int field2;
    private float field3;


    static {
        System.out.println("A static init");
    }


    public A() {
        System.out.println(" A construct ");
    }

    public A(String field1) {
        this.field1 = field1;
    }

    public A(String field1, int field2) {
        this.field1 = field1;
        this.field2 = field2;
    }

    public A(String field1, int field2, float field3) {
        this.field1 = field1;
        this.field2 = field2;
        this.field3 = field3;
    }
}

第一種通過(guò)Class.forName(name) 加載class，對(duì)于字節(jié)加載到類(lèi)加載器的過(guò)程，主要體現(xiàn)在靜態(tài)區(qū)域的初始化，測(cè)試結(jié)果也顯示，會(huì)調(diào)用靜態(tài)快
如果使用第二種方法，將初始參數(shù)設(shè)置為false，則不會(huì)調(diào)用靜態(tài)塊，從而可以得出結(jié)論，文檔中所說(shuō)的初始化主要是指靜態(tài)塊。
在這兩者調(diào)用的過(guò)程中，都會(huì)去調(diào)用構(gòu)造方法，也證明，構(gòu)造方法主要是實(shí)例化對(duì)象的時(shí)候才會(huì)被調(diào)用，在Class中從newInstance方法就能體現(xiàn)出來(lái)。