import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
public class Test {
public static void main(String[] args) {
try {
Class clazz = Class.forName("java.lang.StringBuffer");
Object obj = clazz.newInstance();
Class[] paramTypes = { String.class };
Method mm = clazz.getDeclaredMethod("append", paramTypes);
mm.invoke(obj, new Object[] {"hello, world"});
System.out.println(obj);
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (InstantiationException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (SecurityException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
}