问为什么这会陷入无限循环？

public class Tests {

    public static void main(String[] args) throws Exception {

        int x = 0;

        while(x<3) {

            x = x++;

            System.out.println(x);

        }

    }

}

public class Tests extends java.lang.Object{

public Tests();

  Code:

   0:   aload_0

   1:   invokespecial   #1; //Method java/lang/Object."<init>":()V

   4:   return

public static void main(java.lang.String[])   throws java.lang.Exception;

  Code:

   0:   iconst_0

   1:   istore_1

   2:   iload_1

   3:   iconst_3

   4:   if_icmpge   22

   7:   iload_1

   8:   iinc    1, 1

   11:  istore_1

   12:  getstatic   #2; //Field java/lang/System.out:Ljava/io/PrintStream;

   15:  iload_1

   16:  invokevirtual   #3; //Method java/io/PrintStream.println:(I)V

   19:  goto    2

   22:  return

}