Programming Forums > Application Development > Java

Lakrids · May 7th, 2008, 5:33 AM

Hello,

I am writing a program which needs at a certain point the use of priority queues. For that I use java.util.PriorityQueue. The problem is that javac refuses to compile my code, and I just don't understand why. For the following code :

 java Syntax (Toggle Plain Text) 
// ...
import java.util.PriorityQueue;
// ...
// ...
import java.util.PriorityQueue;
// ...

it says

(Toggle Plain Text)

Error : The import java.util.PriorityQueue cannot be resolved

WHY? It is supposed to be there!!
Even with

 java Syntax (Toggle Plain Text) 
// ...
import java.util.*;
// ...
PriorityQueue q = new PriorityQueue();
// ...
import java.util.*;
// ...
PriorityQueue q = new PriorityQueue();

or

 java Syntax (Toggle Plain Text) 
// ...
import java.*;
// ...
PriorityQueue q = new PriorityQueue();
// ...
import java.*;
// ...
PriorityQueue q = new PriorityQueue();

it gives

(Toggle Plain Text)

Error : PriorityQueue cannot be resolved to a type

What is the problem?

Sane · May 7th, 2008, 5:49 AM

Some quick googling suggested that maybe you don't have the version of Java which supports Priority Queues. I am not sure, so maybe you could verify that for me, and/or see if there is a version which doesn't support them.

Lakrids · May 7th, 2008, 7:26 AM

Yup, apparently I don't have the "Java Collections Framework", which includes the PriorityQueue class, which is very weird, because I thought I installed everything java-related.

Well, thanks for pointing it out!

Sane · May 7th, 2008, 8:09 AM

No problem. Lucky guess.

andro · May 7th, 2008, 11:21 AM

You need at least Java 1.5

May 7th, 2008, 5:33 AM	#1
Lakrids Newbie Join Date: Dec 2007 Posts: 23 Rep Power: 0	PriorityQueue problem Hello, I am writing a program which needs at a certain point the use of priority queues. For that I use java.util.PriorityQueue. The problem is that javac refuses to compile my code, and I just don't understand why. For the following code : java Syntax (Toggle Plain Text) // ... import java.util.PriorityQueue; // ... // ... import java.util.PriorityQueue; // ... it says (Toggle Plain Text) Error : The import java.util.PriorityQueue cannot be resolved Error : The import java.util.PriorityQueue cannot be resolved WHY? It is supposed to be there!! Even with java Syntax (Toggle Plain Text) // ... import java.util.; // ... PriorityQueue q = new PriorityQueue(); // ... import java.util.; // ... PriorityQueue q = new PriorityQueue(); or java Syntax (Toggle Plain Text) // ... import java.; // ... PriorityQueue q = new PriorityQueue(); // ... import java.; // ... PriorityQueue q = new PriorityQueue(); it gives (Toggle Plain Text) Error : PriorityQueue cannot be resolved to a type Error : PriorityQueue cannot be resolved to a type What is the problem?

May 7th, 2008, 5:49 AM	#2
Sane Programming Guru Join Date: Apr 2005 Posts: 1,722 Rep Power: 5	Re: PriorityQueue problem Some quick googling suggested that maybe you don't have the version of Java which supports Priority Queues. I am not sure, so maybe you could verify that for me, and/or see if there is a version which doesn't support them. __________________ Waterloo's Canadian Computing Competition (CCC) - Stage 2 Problems, Solutions, and Test Data

May 7th, 2008, 7:26 AM	#3
Lakrids Newbie Join Date: Dec 2007 Posts: 23 Rep Power: 0	Re: PriorityQueue problem Yup, apparently I don't have the "Java Collections Framework", which includes the PriorityQueue class, which is very weird, because I thought I installed everything java-related. Well, thanks for pointing it out!

May 7th, 2008, 8:09 AM	#4
Sane Programming Guru Join Date: Apr 2005 Posts: 1,722 Rep Power: 5	Re: PriorityQueue problem No problem. Lucky guess. __________________ Waterloo's Canadian Computing Competition (CCC) - Stage 2 Problems, Solutions, and Test Data

May 7th, 2008, 11:21 AM	#5
andro Professional Programmer Join Date: Oct 2005 Location: California Posts: 280 Rep Power: 3	Re: PriorityQueue problem You need at least Java 1.5 __________________ http://www.kevinherron.com/

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Programming Forums > Application Development > Java

PriorityQueue problem