The type HashMap is not generic; it cannot be parameterized with arguments <String, Integer>

Question

This is a strange error I am getting today when I try to implement a Map as below.

Map<String, Integer> cache = new HashMap<String, Integer>();

I am using JDK 1.7 and not sure why this error has been coming. Changing the above line by adding a cast removes the error. I looked at the related posts on stackoverflow before posting this question. Seems to be a strange issue.

Map<String, Integer> cache = (Map<String, Integer>) new HashMap();

Are you sure both Map and HashMap come from java.util package in your code? — Luiggi Mendoza
– Luiggi Mendoza, Commented Sep 24, 2013 at 14:51
@Shane - What is the error ? Are you using any IDE like eclipse ? — Sachin Thapa
– Sachin Thapa, Commented Sep 24, 2013 at 14:51
Are you declaring your own non-generic HashMap class anywhere? Please provide a short but complete program demonstrating the problem. — Jon Skeet
– Jon Skeet, Commented Sep 24, 2013 at 14:54
I was getting the same error. In my case, I had given my class the same name i.e created a class labeled HashMap. This was conflicting with the java.util.HasMap. make sure your class name is different — Bhardwaj Joshi
– Bhardwaj Joshi, Commented Feb 10, 2019 at 10:11

Alfredo Osorio · Accepted Answer · 2013-09-24 14:51:20Z

30

Check you are actually using java.util.HashMap and java.util.Map in your imports.

answered Sep 24, 2013 at 14:51

Alfredo Osorio

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Comments

ByteWelder · Accepted Answer · 2016-06-22 12:25:54Z

8

I have also gone through the same error but it was resolved just by changing some properties of the project:

Right-click on your project
Click on Properties
Select Java Build Path from right-hand side panel
Select Order and Export tab
Click on your JRE System Library or JDK Library
Click on Up button and move it to first position
Click Ok
Clean & build your project.

Do repeat this for all other dependents project as well, if you have dependencies.

It resolved my issue because previously the Java files were picking other libraries and packages not from JRE package as it was ordered set in last priority.

edited Jun 22, 2016 at 12:25

ByteWelder

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answered Jun 22, 2016 at 11:45

Shwetank Rastogi

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Adam Arold · Accepted Answer · 2013-09-24 15:01:01Z

3

I'm sure that you are importing the wrong HashMap. You have to use the java.util packages for the code you presented there.

We can't help you any further without seeing your import statements.

answered Sep 24, 2013 at 15:01

Adam Arold

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Omkar · Accepted Answer · 2020-11-15 10:24:21Z

2

The type HashMap is not generic; it cannot be parameterized with arguments <String, Integer>

If this type of error occur than first check your file name and class name Beause by mistake you save file name as HashMap.java Than try other ways

answered Nov 15, 2020 at 10:24

Omkar

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2 Comments

Tzach Solomon Over a year ago

what do you mean by HashMap is not generic. The definition of java.util.HashMap is: public class HashMap<K,V> extends AbstractMap<K,V>

Tomer Shetah Over a year ago

Welcome to SO! Please read the tour, and How do I write a good answer?

Neeraj Pandey · Accepted Answer · 2016-08-23 20:27:14Z

0

If none of the above solution works ,the only possible reason you are getting this error is because you might have named your class_name similar to an already existing class which is either in util or lang library .

answered Aug 23, 2016 at 20:27

Neeraj Pandey

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pnkj · Accepted Answer · 2018-12-29 10:51:44Z

0

Recently, I have met the same problem.Almost I have found all the answers, but I failed.
I had imported java.util.HashMap and java.util.Map or set the JRE System Library to the top.But in vain.

At last, I tried to change my Class name from HashMap to HashMapDemo. Now, I just want to tell you that your Class name may be one of the java.util.*, you should change your Class name.

edited Dec 29, 2018 at 10:51

user3956566

answered Dec 29, 2018 at 8:24

pnkj

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sergiotarxz · Accepted Answer · 2018-12-29 11:27:42Z

0

If you have named your class with the same name as other class you can always do the following:

Map<String, Integer> cache = new java.util.HashMap<String, Integer>();

It's a common mistake when you are trying a new language/library capability to call the class with the same name as the class you are trying, anyway this is not only useful to this purpose.

For example there are multiple classes name Date like Java.sql.Date and java.util.Date, in this case if you need to reference both it's useful to know that.

answered Dec 29, 2018 at 11:27

sergiotarxz

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helvete · Accepted Answer · 2020-10-16 00:34:56Z

0

Never name or keep your class name same as any class which is predefined in Java Util.

For example: In Java HashMap is predefined class and if create a new class with same name i.e HashMap then it's obvious to get such error.

edited Oct 16, 2020 at 0:34

helvete

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answered Aug 9, 2018 at 4:35

Ankush kumar

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1 Comment

franiis Over a year ago

Welcome on SO. When answering to questions, try to adress the question, not other answers.

Ravenix · Accepted Answer · 2020-10-16 09:31:58Z

0

Try with this:

Create a new class and give some another unique name in same package
import - import java.util.*; or import java.util.HashMap;
create HashMap as:

HashMap<Integer,String> map=new HashMap<Integer,String>(); (old verbose way)

or

HashMap<String, Integer> map = new HashMap<>(); (better way)

or

Map<String, Integer> map = new HashMap<>(); (best way)

compile and run

edited Oct 16, 2020 at 9:31

Ravenix

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answered Oct 15, 2020 at 12:08

Rahul Nigam

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user2367418 · Accepted Answer · 2021-02-16 07:46:18Z

0

This can happen when the Java version you compile to is lower than your JDK. Make sure the "compiler compliance level", as Eclipse calls it, is high enough. This happened to me. The problem happened in Eclipse when my JDK was Java 7, but the compiler compliance level was at 1.4. On my Eclipse this setting is at Project->Properties->Java Compiler. I raised the compiler compliance level to 6.0 and the problem went away.

edited Feb 16, 2021 at 7:46

answered Feb 16, 2021 at 7:40

user2367418

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ritu mansata · Accepted Answer · 2022-01-17 04:57:48Z

0

use java.util.Map.<String, Integer> cache = new HashMap<String, Integer>(); and import import java.util.*;

answered Jan 17, 2022 at 4:57

ritu mansata

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1 Comment

Ruli Over a year ago

This answer does not bring anything new to the thread, similar solution was already proposed for example in this answer: stackoverflow.com/a/53969107/3157428

Pratik Burghate OG · Accepted Answer · 2023-01-13 12:47:52Z

0

If your using vs code and you forgot to install vs code for java package first do that.
Change your class name to something different than the name present in your src folder. do not name it HashMap.java.
import java.util.HashMap; there you go it will fix the problem, it did for me.

answered Jan 13, 2023 at 12:47

Pratik Burghate OG

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Comments

Vivek Yadav · Accepted Answer · 2024-10-12 18:22:27Z

0

The type Map is not generic; it cannot be parameterized with arguments <String, Integer>

This Error Occurs Due To Your Project File Name Check Your File And Change That.

And Import

import java.util.Map;

It Will Work For Me

answered Oct 12, 2024 at 18:22

Vivek Yadav

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allen gay · Accepted Answer · 2014-10-19 17:29:39Z

-1

I did something really stupid to get this error. You might check. I named my class "HashMap" lol. You might check that.

answered Oct 19, 2014 at 17:29

allen gay

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