How to use an older version of Java (not the default) with a Maven project on NetBeans 8

I need to use Java 6, but NetBeans doesn't use it even after all the configurations I've done. It keeps running Maven with Default, which is Java 8 for my IDE. The same configuration works well on Eclipse, so I don't understand what I am doing wrong.

I don't want to define the compiler in the nb-configuration.xml file as I will need to commit the file. I would expect NetBeans to get this from the POM.

General information:

• I am using NetBeans 8.0.1 (completely updated), running Java 8
• NetBeans 8 needs JDK 7+ to work
• Using Maven 3.2.3 but built in (Maven 3.0.5 doesn't work either)
• All Maven plugins updated

To reproduce, simply create any type of Maven project in NetBeans. In my case, I tried using Java, Web and EJB, but none worked.

The following figure shows that the JDK is correctly added to the IDE.

Tools> Java Platforms

Added JDK 1.6.

The POM configs I've tried:

Properties

<properties>
    <maven.compiler.source>1.6</maven.compiler.source>
    <maven.compiler.target>1.6</maven.compiler.target>
</properties>

      

        
        
        
      

    

Compiler plugin

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.2</version>
        <configuration>
            <source>1.6</source>
            <target>1.6</target>
        </configuration>
    </plugin>

      

        
        
        
      

    

Enforcer plugin

Forcing Java 6 implementation gives the following error:

Detected JDK Version: 1.8.0-25 is not in the allowed range [1.6,1.7).
------------------------------------------------------------------------
BUILD FAILURE

      

        
        
        
      

    

Operator configuration:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-enforcer-plugin</artifactId>
        <version>1.3.1</version>
        <executions>
            <execution>
                <id>enforce-versions</id>
                <goals>
                    <goal>enforce</goal>
                </goals>
                <configuration>
                    <rules>
                        <requireJavaVersion>
                            <version>[1.6,1.7)</version>
                        </requireJavaVersion>
                    </rules>
                </configuration>
            </execution>
        </executions>
    </plugin>

      

        
        
        
      

    

Test code for Java 6

The following code shouldn't compile:

import java.nio.file.Files;
import java.time.LocalTime;

public class JavaVersionChecker {

    public static void main(String[] args) {

        System.out.println(Files.class); // Java 7 API
        System.out.println("Time: " + LocalTime.now()); // Java 8 API

        // Print Java version
        System.out.println(System.getProperty("java.version"));
    }

}

      

        
        
        
      

    

Test output

Compiled test code with Java 7 and 8 APIs, but only Java 6 should be accepted.

------------------------------------------------------------------------
Building java6_project 1.0-SNAPSHOT
------------------------------------------------------------------------

--- exec-maven-plugin:1.2.1:exec (default-cli) @ java6_project ---
class java.nio.file.Files
Time: 19:24:05.997
1.8.0_25
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 0.610 s
Finished at: 2014-11-21T19:24:06-02:00
Final Memory: 6M/123M
------------------------------------------------------------------------

      

        
        
        
      

    

JDK 6 should be detected by the IDE