Sander_M Sander_M - 17 days ago 6
Java Question

Byte Buddy - java.lang.NoSuchMethodException - what is the correct defineMethod syntax?

I am trying to create a setter and a getter for a field using Byte Buddy.

public class Sample {

public static void main(String[] args) throws InstantiationException, IllegalAccessException, NoSuchFieldException, SecurityException, NoSuchMethodException {

Class<?> type = new ByteBuddy()
.subclass(Object.class)
.name("domain")
.defineField("id", int.class, Visibility.PRIVATE)
.defineMethod("getId", int.class, Visibility.PUBLIC).intercept(FieldAccessor.ofBeanProperty())
.make()
.load(Sample.class.getClassLoader(), ClassLoadingStrategy.Default.WRAPPER)
.getLoaded();

Object o = type.newInstance();
Field f = o.getClass().getDeclaredField("id");
f.setAccessible(true);
System.out.println(o.toString());
Method m = o.getClass().getDeclaredMethod("getId", int.class);
System.out.println(m.getName());
}
}


In the accessing field section of the learn pages here it is stated that creating a setter and getter is trivial by using an
implementation
after defining the method and then using
FieldAccessor.ofBeanProperty()


The
Method m = o.getClass().getDeclaredMethod("getId", int.class);
throws the NoSuchMethodException.

What is the correct syntax for creating a getter and a setter?

Answer

The correct method call should be

Method m = o.getClass().getDeclaredMethod("getId");

int is the return type, and you don't have to specify the return type in the getDeclaredMethod call - only the argument types and the method getId has no arguments.