Set field value with Reflection « Field « Reflection

Return	Method	Summary
void	set(Object obj, Object value)	Sets the field value.
void	setBoolean(Object obj, boolean z)	Sets boolean field value.
void	setByte(Object obj, byte b)	Sets byte field value.
void	setChar(Object obj, char c)	Sets char field value.
void	setDouble(Object obj, double d)	Sets double field value.
void	setFloat(Object obj, float f)	Sets float field value.
void	setInt(Object obj, int i)	Sets int field value.
void	setLong(Object obj, long l)	Sets long field value.
void	setShort(Object obj, short s)	Sets short field value.


import java.awt.Rectangle;
import java.lang.reflect.Field;

public class Main {

  public static void main(String[] args) {
    Rectangle r = new Rectangle(100, 325);
    Class c = r.getClass();
    try {
      Field heightField = c.getField("height");
      heightField.setInt(r, 1000);
      Integer heightValue = (Integer) heightField.get(r);
      System.out.println("Height: " + heightValue.toString());
    } catch (NoSuchFieldException e) {
      System.out.println(e);
    } catch (SecurityException e) {
      System.out.println(e);
    } catch (IllegalAccessException e) {
      System.out.println(e);
    }
  }
}