Error in compilation of code with lambda expression

Question

I have the following code:

package com.mongoDB;

import spark.Spark;

public class HelloWorldSparkStyle {
   public static void main(String[] args) {
       Spark.get("/hello", (req, res) -> "Hello World");
   }
}

It runs fine when I run it through main method but throws the following error when I try to compile it:

\HelloWorldSparkStyle.java:[9,33] error: lambda expressions are not supported in -source 1.5

D:\WorkspaceWithJava8\BeginnerProject>javac -version
javac 1.8.0_60

I am using Eclipse IDE and trying to compile it through command line.

which version of eclipse or netbeans you use?

Ajay Pandya
– Ajay Pandya

2015-10-26 09:55:45 +00:00
Commented Oct 26, 2015 at 9:55 — Ajay Pandya
– Ajay Pandya, Commented Oct 26, 2015 at 9:55

Tunaki · Accepted Answer · 2015-10-26 09:55:46Z

6

By default, the maven-compiler-plugin uses Java 5 to compile the classes. Quoting its documentation:

Also note that at present the default source setting is 1.5 and the default target setting is 1.5, independently of the JDK you run Maven with. If you want to change these defaults, you should set source and target as described in Setting the -source and -target of the Java Compiler.

You need to configure it to use Java 8, like this:

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>3.3</version>
    <configuration>
      <source>1.8</source>
      <target>1.8</target>
    </configuration>
</plugin>

answered Oct 26, 2015 at 9:55

Tunaki

138k46 gold badges370 silver badges443 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Ondro Mihályi Over a year ago

More concise way of setting these parameters is via properties:

<properties>   <maven.compiler.source>1.8</maven.compiler.source>   <maven.compiler.target>1.8</maven.compiler.target> </properties>

Malinda · Accepted Answer · 2016-02-27 14:10:22Z

1

Let me elaborate above answer further. Put the plugin given in above answer between <project> and </project> as below.

<build>
<plugins>
    <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.3</version>
        <configuration>
            <source>1.8</source>
            <target>1.8</target>
        </configuration>
    </plugin>
</plugins>
</build>

answered Feb 27, 2016 at 14:10

Malinda

3663 silver badges13 bronze badges

Collectives™ on Stack Overflow

Error in compilation of code with lambda expression

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related