Untitled Document

Question 1:
Why would the ability to set access of a variable using the setAccessible() method be a problem?

Highlight to see answer!
Solution: By default java applications do not install a security manager. This means that anyone can simply call setAccessible(true) to any field in your class and change the data as they wish, presenting a huge security risk to any software using Reflection.

Question 2:
Given a class:
```
		  		public Class A
				{
					private int x;
					public A()
					{
						x=0;
					}
					public void add(int y)
					{
						x += y;
					}
				}
		  	
```
In a java main add 1 to the field x using Reflection in 2 ways. The first being set the access of the field to allow you to simply add it directly. And second to get the method provided in the class and add 1 to x that way. You will need to define an object A in your main to do one of the methods. Also remember to get the Class of a primitive, such as an int, use Integer.TYPE.

Solution: (There are multiple ways you could have gotten the class)

  		static void main(String args[])
		{
			A obj = new A();
			/** First Way **/
			try
			{
				Class cls = Class.forName("A");
				Field fld = cls.getDeclaredField("x");
				fld.setAccessible(true);
				Object value = fld.get(obj);
				fld.set(obj,(Integer)value+1);
			}
			catch(Throwable e)
			{
				System.err.prinln(e);
			}
			/** Second way **/
			Method m = cls.getDeclaredMethod("add",Integer.TYPE);
			m.invoke(A,1);
		}