java泛型不是计算运行时的数据类型

package com.ada.data.entity;

import java.io.Serializable;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
public class NumEntity<NUM extends Number> implements Serializable {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	private NUM id;

	public NUM getId() {
		return id;
	}

	public void setId(NUM id) {
		this.id = id;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((id == null) ? 0 : id.hashCode());
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		NumEntity other = (NumEntity) obj;
		if (id == null) {
			if (other.id != null)
				return false;
		} else if (!id.equals(other.id))
			return false;
		return true;
	}

}

package com.tongna.rest.apps;

import com.ada.data.entity.NumEntity;

public class A extends NumEntity<Long> {

}

A a = new A();
		a.setId(1l);
		Class<?> ccc = a.getClass().getMethod("getId").getReturnType();
		System.out.println(ccc);
		System.out.println(a.getId().getClass());

java泛型不是计算运行时的数据类型。

所以在使用BeanUtils.copyProperties(source, result);的时候id不能拷贝。