Java technology improvement, review, and summary (2)

Java technology improvement, review, and summary (2)

Next reflection:

Array reflection, also see the code comprehension:

int [] a1 = new int[]{1,2,3};int [] a2 = new int[4];int[][] a3 = new int[2][3];String [] a4 = new String[]{"a","b","c"};System.out.println(a1.getClass() == a2.getClass());System.out.println(a1.getClass() == a4.getClass());System.out.println(a1.getClass() == a3.getClass());System.out.println(a1.getClass().getName());System.out.println(a1.getClass().getSuperclass().getName());System.out.println(a4.getClass().getSuperclass().getName());Object aObj1 = a1;Object aObj2 = a4;//Object[] aObj3 = a1;Object[] aObj4 = a3;Object[] aObj5 = a4;System.out.println(a1);System.out.println(a4);System.out.println(Arrays.asList(a1));System.out.println(Arrays.asList(a4));printObject(a4);printObject("xyz");

Private static void printObject (Object obj) {Class clazz = obj. getClass (); if (clazz. isArray () {int len = Array. getLength (obj); for (int I = 0; I
 
  

  
4: ArrayList and HashSet
  

  
                Collection collections = new HashSet();ReflectPoint pt1 = new ReflectPoint(3,3);ReflectPoint pt2 = new ReflectPoint(5,5);ReflectPoint pt3 = new ReflectPoint(3,3);collections.add(pt1);collections.add(pt2);collections.add(pt3);collections.add(pt1);
  
              System.out.println(collections.size());
  
      public class ReflectPoint {private int x;public int y;
  

  

  
public ReflectPoint(int x, int y) {super();this.x = x;this.y = y;}@Overridepublic int hashCode() {final int prime = 31;int result = 1;result = prime * result + x;result = prime * result + y;return result;}@Overridepublic boolean equals(Object obj) {if (this == obj)return true;if (obj == null)return false;if (getClass() != obj.getClass())return false;final ReflectPoint other = (ReflectPoint) obj;if (x != other.x)return false;if (y != other.y)return false;return true;}}