I need to compile some of my Maven projects to be JDK 1.4 compatible, some for JDK 1.5 or JDK 1.6. To do this in Maven is very straight forward since I have different pom.xml for different applications.

I write my code using JDK 1.5 syntax but I need the library to be JDK 1.4 compatible, so here is my configuration.

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.0.2</version>
    <configuration>
        <source>1.5</source>
        <target>jsr14</target>
    </configuration>
</plugin>

To compile it to be JDK 1.5 compatible,

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.0.2</version>
    <configuration>
        <source>1.5</source>
        <target>1.5</target>
    </configuration>
</plugin>

To compile it to be JDK 1.6 compatible
To compile it to be JDK 1.5 compatible,

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.0.2</version>
    <configuration>
        <source>1.6</source>
        <target>1.6</target>
    </configuration>
</plugin>