Set default java compliance level for Maven projec

Question

The default compliance level for Maven is 1.5 and every time that I update a maven project in Eclipse it sets back the compliance level from 1.6 to 1.5 which is really annoying for me.

I know that I can set the target to 1.6 in the POM file but the problem is that I cannot set this in the parent POM and expect the children to inherit it. So I have to do it for every single Maven module. How can I set it in my Maven project or in the whole eclipse once for a "lifetime" without modifying every single Maven module!?

Answer 1

Another way (if you do not have already compiler plugin defined) is to set just these properties in your pom file:

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

Details: https://maven.apache.org/plugins/maven-compiler-plugin/examples/set-compiler-source-and-target.html

Answer 2

Go to the project's pom.xml and insert below in between tags. Then the eclipse plugin (like m2eclipse) should rebuild the workspace.

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>

    </plugins>
</build>

Note: this is project-level as only the project's pom.xml is affected.

Answer 3

I know that I can set the target to 1.6 in pom file but the problem is that I cannot set this in the parent pom and expect the children to inherit it.

Setting the <source> and <target> version in the parent pom does work.

For example, in my parent pom, I have:

<pluginManagement>
  <plugins>
    <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-compiler-plugin</artifactId>
      <version>2.3.2</version>
      <configuration>
        <source>1.6</source>
        <target>1.6</target>
        <encoding>UTF-8</encoding>
      </configuration>
    </plugin>
  </plugins>
</pluginManagement>

If you are having problems, you might want to check that:

• the child specifies the correct version of the parent;
• the parent pom specifies both source and target values;
• you have run mvn install on the parent; and
• mvn help:effective-pom on the child project shows the expected source/target values.

After modifying the poms, you may need to select both projects and use Maven->Update Project.

Answer 4

This worked for me..

<build>
<finalName>ProjectName</finalName>
<plugins>
   <plugin>
       <groupId>org.apache.maven.plugins</groupId>
       <artifactId>maven-compiler-plugin</artifactId>
       <version>2.3.1</version>
       <configuration>
           <source>1.6</source>
           <target>1.6</target>
       </configuration>
   </plugin>
</plugins>
</build>