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

Answer 1

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.

Answer 2

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).

Answer 3

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

Answer 4

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.

Answer 5

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

Answer 6

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