Why is java var type variables not working?

Question

I declared var type variable however the program throws compilation error. Can someone suggest the reason for this error?

var avg2 = 10.0;

Error:

javac "VarTypeVariables.java" (in directory: S:\29032020 Java\12 Var Type Variables)
VarTypeVariables.java:12: error: cannot find symbol
        var avg2 = 10.0; //type based on 10.0 (i.e double)
        ^
  symbol:   class var
  location: class VarTypeVariables
1 error
Compilation failed.

Code:

class VarTypeVariables {
    public static void main (String args[]){
        var avg2 = 10.0; 
    }
}

@Eran I have : C:\Users\Sandun_S_V>java -version java version "1.8.0_121" Java(TM) SE Runtime Environment (build 1.8.0_121-b13) Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode) — Sandun Sampath Vitharana
– Sandun Sampath Vitharana, Commented Apr 13, 2020 at 6:51
What you show there says you're running Java 8. You need to upgrade to Java 10 or newer to be able to use var — ernest_k
– ernest_k, Commented Apr 13, 2020 at 6:55

DaveH · Accepted Answer · 2020-04-13 06:56:24Z

2

The output from the java -version command you posted above indicates you are using Java 8. var was only introduced in to the language at java 10.

If you want to use var you need to install a more recent version of Java - Java 10 or above.

answered Apr 13, 2020 at 6:56

DaveH

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CodeScale · Accepted Answer · 2020-04-13 06:55:18Z

0

var keyword was added in java 10 for type inference. You have to upgrade to this version of java to make this example working.

answered Apr 13, 2020 at 6:55

CodeScale

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backdoor · Accepted Answer · 2020-04-13 06:55:32Z

0

The reason may be you are using an older version of java. In Java 10, the var keyword has been introduced. e.g. instead of doing String str = "Java", you can now just say var str = "Java".

answered Apr 13, 2020 at 6:55

backdoor

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Suleiman Divério Sallum · Accepted Answer · 2024-01-15 01:19:38Z

0

I already had the Java 17 version in use and it still didn't work. So I made the settings below and it worked.

Add to pom.xml:

<maven.compiler.release>17</maven.compiler.release>
<java.version>17</java.version>

Go to: Settings > Build, Execution, Deployment > Compiler > Java Compiler

IMG

edited Jan 15, 2024 at 1:19

answered Jan 15, 2024 at 1:17

Suleiman Divério Sallum

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Crystyan S. Santos · Accepted Answer · 2024-02-17 21:20:56Z

0

I get the same error using java 17. I change java version on spring boot project in the same moment the project was running. And after this state showed up.

To fix this, change java version again e clean your project with > mvn clean, after reload the project and its done!

answered Feb 17, 2024 at 21:20

Crystyan S. Santos

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