The "import java.util.function cannot be resolved" error

Question

I'm trying to run this practice script from the standard Oracle Java tutorials.

This seems to be a common error and I've used SO resources to make attempts to fix this. I've tried Cleaning the project, refreshing the project, switch workplace and switch back, removed and re-added the JRE7.

I don't know what else to do.

import java.util.List;
import java.util.function.Consumer; -----> cannot be resolved ERROR
import java.util.function.Function; -----> cannot be resolved ERROR
import java.util.Comparator;
import java.util.function.Predicate; -----> cannot be resolved ERROR
import java.lang.Iterable;
import java.time.chrono.IsoChronology; -----> cannot be resolved ERROR

public class LambdaExpressions_RosterTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub

    }

    }

All four packages come from Java 8. You need to configure SDK to reference Java 8 to fix this error. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Aug 5, 2014 at 1:02
I'm new at this. How can you tell what you are running? I'm using Eclipse Android Developer Tools... — StacyM
– StacyM, Commented Aug 5, 2014 at 1:03

Elliott Frisch · Accepted Answer · 2014-08-05 01:09:21Z

16

Per the java.util.function Javadoc,

Since:
      1.8

So upgrade to Java 8, or try to find an older version of the tutorial.

I'm new at this. How can you tell what you are running? I'm using Eclipse

To determine your current Java version in eclipse, go to

Help -> About Eclipse -> Installation Details (Button in
          lower Left) -> Configuration pane

Look for the line java.specification.version - on my machine that is

java.specification.version=1.8

Or the line java.runtime.version - on my machine that is

java.runtime.version=1.8.0_11-b12

edited Aug 5, 2014 at 1:09

answered Aug 5, 2014 at 1:04

Elliott Frisch

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7 Comments

StacyM Over a year ago

In Eclipse, how can I tell what Java I'm running?

StacyM Over a year ago

I'm running, Eclipse with ADT. It's different from those steps. I'm digging at this now...

Jan Nielsen Over a year ago

Right click on project, then properties, then Java Compiler, and note the "Compiler compliance level". If you don't see 1.8 available, install it first, then add it to Eclipse, and then it'll be available to you.

Elliott Frisch Over a year ago

@StacyM Windows x86 - the Offline version can be used to save yourself a lot of time if you're installing on multiple machines, the Online version downloads the Java installation content dynamically during installation.

StacyM Over a year ago

Figured it out! Window - Preferences - Java - Installed JREs - Add Standard VM - path to C: Program Files\Java\jre8.

|

SoftwareDev · Accepted Answer · 2014-09-24 09:12:36Z

15

i solved this problem by trying following solution

Project > Properties > Java Build Path
Select Libraries tab
Select JRE System Library
Click Edit button
Choose an alternate JRE (jre1.8.0_20)
Click Finish button

answered Sep 24, 2014 at 9:12

SoftwareDev

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1 Comment

Er Rahul Raj Over a year ago

Saved me, I struggled serious 3 hours, solved using your above given suggestion, Thanks a lot!!

Tapan Pandya · Accepted Answer · 2014-08-05 01:07:11Z

4

Lambda Expressions are newly added into Java 8. They are not available for JRE7. Try to upgrade your eclipse project's JRE to 8 (window -> preferences->java->compiler).

answered Aug 5, 2014 at 1:07

Tapan Pandya

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Yash Jagdale · Accepted Answer · 2018-04-23 07:43:03Z

1

For idea IntelliJ you need to go to Menu-> Project Structure -> Module here you will see Source tab, above this tab you can see language level. change it to more than 8.

-yash

answered Apr 23, 2018 at 7:43

Yash Jagdale

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Comments

IVIike · Accepted Answer · 2019-11-21 07:20:08Z

1

I had something similar with Apache Camel: the following function was not working anymore

String headerKey = exchange.getIn().getHeader("headerKey",String.class);

because of the error-message:

The type java.util.function.Supplier cannot be resolved. It is indirectly referenced from required .class files

To solve the issue I change the casting and it worked afterwards:

String headerKey = (String) exchange.getIn().getHeader("headerKey");

maybe it helps you or somebody else.

One other point to mention here would be the Apache Camel version itself as stated on the official page linked here.

edited Nov 21, 2019 at 7:20

answered Aug 3, 2018 at 5:56

IVIike

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Salahuddin Quazi · Accepted Answer · 2015-02-03 07:31:44Z

0

same problem is coming to me,I make a changes in eclipse.ini file and did -Dosgi.requiredJavaVersion=1.8 instead of -Dosgi.requiredJavaVersion=1.6 and my problem has been resolved.

answered Feb 3, 2015 at 7:31

Salahuddin Quazi

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shivakumar · Accepted Answer · 2018-02-07 17:26:45Z

0

Ran into this problem when the version I was using in the below properties was <1.8. Updating my POM to a version >1.8 resolved my issue.

<properties>
     <maven.compiler.source>1.9</maven.compiler.source>
     <maven.compiler.target>1.9</maven.compiler.target>
</properties>

answered Feb 7, 2018 at 17:26

shivakumar

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TylerH · Accepted Answer · 2018-02-23 19:46:21Z

0

I ran into this while trying to use Java 9 with Eclipse Oxygen. Eclipse claimed that I was using less than Java 1.8 and asked if I wanted to use 1.8. Saying yes solved the problem, but led to this error message later on.

I went in to Window => Preferences => Java => Compiler and saw that this had been changed to 1.8, so I changed it back to 9 and everything seems to be working now.

edited Feb 23, 2018 at 19:46

TylerH

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answered Feb 23, 2018 at 19:25

cowang

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