有趣的java-大家伙儿一起来猜猜看结果？（如果你有结果请给出你的解释）

有趣的java-大家一起来猜猜看结果？（如果你有结果请给出你的解释）
案例一:

class Test
{
	  private static Test test = new Test();
	  
	  public static int counter1;
	  
	  public static int counter2 = 0;
	  
	  public Test()
	  {
		  counter1++;
		  counter2++;
	  }
	  
	  public static Test getInstance()
	  {
		return test;  
	  }
}
public class ClassLoadTest {
	public static void main(String[] args)
	{
		Test test = Test.getInstance();
		System.out.println("counter1\t"+Test.counter1);
		System.out.println("counter2\t"+Test.counter2);
	}
}

案例二:

class Test
{
	
	  public static int counter1;
	  
	  public static int counter2 = 0;

        private static Test test = new Test();
	  
	  public Test()
	  {
		  counter1++;
		  counter2++;
	  }
	  
	  public static Test getInstance()
	  {
		return test;  
	  }
}
public class ClassLoadTest {
	public static void main(String[] args)
	{
		Test test = Test.getInstance();
		System.out.println("counter1\t"+Test.counter1);
		System.out.println("counter2\t"+Test.counter2);
	}
}

案例三：

abstract class A{
	public A(){
		this.print() ;
	}
	public abstract void print() ;
};
class B extends A{
	private int x = 100 ;
	public B(int x){
		this.x = x ;
	}
	public void print(){
		System.out.println("x = " + x) ;
	}
};
public class TestJava{
	public static void main(String args[]){
		A a = new B(10) ;
	}
};