code: @Test public void constructorTest(){
    obj[0]=strType;
    obj[1]=integerType;
    obj[2]=longType;
    obj[3]=doubleType;
    obj[4]=boolType;
    obj[5]=charType;
    for (int j=0; j < obj.length - 1; j++) {
      for (int k=j + 1; k < obj.length; k++) {
        Pair tPair=new Pair(obj[j],obj[k]);
        Assert.assertEquals(obj[j],tPair.getFirst());
        Assert.assertEquals(obj[k],tPair.getSecond());
        Assert.assertNotSame(obj[k],tPair.getFirst());
        Assert.assertNotSame(obj[j],tPair.getSecond());
      }
    }
  }
  