当我尝试运行此代码时:
import java.io.*;
import java.util.*;
public class TwoColor
{
public static void main(String[] args)
{
Queue<Edge> theQueue = new Queue<Edge>();
}
public class Edge
{
//u and v are the vertices that make up this edge.
private int u;
private int v;
//Constructor method
public Edge(int newu, int newv)
{
u = newu;
v = newv;
}
}
}
我收到此错误:
Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Cannot instantiate the type Queue
at TwoColor.main(TwoColor.java:8)
我不明白为什么我不能实例化该类…这对我来说似乎是对的…
答案
java.util.Queue
是一个接口,因此您无法直接实例化它。LinkedList
:
Queue<T> q = new LinkedList<T>;